diff --git a/build-system/global-configs/canary-config.json b/build-system/global-configs/canary-config.json
index 9f893f8976dc..cc59af44c670 100644
--- a/build-system/global-configs/canary-config.json
+++ b/build-system/global-configs/canary-config.json
@@ -17,6 +17,5 @@
   "visibility-trigger-improvements": 1,
   "fie-resources": 1,
   "ads-initialIntersection": 1,
-  "amp-cid-backup": 1,
-  "sticky-ad-transition": 0.1
+  "amp-cid-backup": 1
 }
diff --git a/build-system/global-configs/prod-config.json b/build-system/global-configs/prod-config.json
index 51f8291abdbe..096b8b3f3f67 100644
--- a/build-system/global-configs/prod-config.json
+++ b/build-system/global-configs/prod-config.json
@@ -12,6 +12,5 @@
   "intersect-resources": 0,
   "ios-fixed-no-transfer": 0,
   "fie-resources": 1,
-  "visibility-trigger-improvements": 1,
-  "sticky-ad-transition": 0.1
+  "visibility-trigger-improvements": 1
 }
diff --git a/build-system/tasks/runtime-test/helpers-unit.js b/build-system/tasks/runtime-test/helpers-unit.js
index 057857da29b2..b33284abfbf2 100644
--- a/build-system/tasks/runtime-test/helpers-unit.js
+++ b/build-system/tasks/runtime-test/helpers-unit.js
@@ -87,9 +87,7 @@ function extractCssJsFileMap() {
  */
 function getImports(jsFile) {
   const jsFileContents = fs.readFileSync(jsFile, 'utf8');
-  const {imports} = listImportsExports.parse(jsFileContents, [
-    'importAssertions',
-  ]);
+  const {imports} = listImportsExports.parse(jsFileContents);
   const files = [];
   const jsFileDir = path.dirname(jsFile);
   imports.forEach(function (file) {
diff --git a/extensions/amp-a4a/0.1/amp-a4a.js b/extensions/amp-a4a/0.1/amp-a4a.js
index 8aecd690ec18..747cae24b46d 100644
--- a/extensions/amp-a4a/0.1/amp-a4a.js
+++ b/extensions/amp-a4a/0.1/amp-a4a.js
@@ -21,10 +21,6 @@ import {DetachedDomStream} from '../../../src/utils/detached-dom-stream';
 import {DomTransformStream} from '../../../src/utils/dom-tranform-stream';
 import {GEO_IN_GROUP} from '../../amp-geo/0.1/amp-geo-in-group';
 import {Layout, LayoutPriority, isLayoutSizeDefined} from '../../../src/layout';
-import {
-  STICKY_AD_TRANSITION_EXP,
-  divertStickyAdTransition,
-} from '../../../src/experiments/sticky-ad-transition-exp';
 import {Services} from '../../../src/services';
 import {SignatureVerifier, VerificationStatus} from './signature-verifier';
 import {
@@ -55,7 +51,6 @@ import {
   getConsentPolicyState,
 } from '../../../src/consent';
 import {getContextMetadata} from '../../../src/iframe-attributes';
-import {getExperimentBranch, isExperimentOn} from '../../../src/experiments';
 import {getMode} from '../../../src/mode';
 import {insertAnalyticsElement} from '../../../src/extension-analytics';
 import {
@@ -69,6 +64,7 @@ import {
 } from '../../../src/utils/intersection';
 import {isAdPositionAllowed} from '../../../src/ad-helper';
 import {isArray, isEnumValue, isObject} from '../../../src/types';
+import {isExperimentOn} from '../../../src/experiments';
 import {listenOnce} from '../../../src/event-helper';
 import {
   observeWithSharedInOb,
@@ -1768,6 +1764,7 @@ export class AmpA4A extends AMP.BaseElement {
       height,
       width
     );
+    this.applyFillContent(this.iframe);
 
     let body = '';
     const transferComplete = new Deferred();
@@ -1857,13 +1854,7 @@ export class AmpA4A extends AMP.BaseElement {
         'title': this.getIframeTitle(),
       })
     ));
-    divertStickyAdTransition(this.win);
-    if (
-      getExperimentBranch(this.win, STICKY_AD_TRANSITION_EXP.id) !==
-      STICKY_AD_TRANSITION_EXP.experiment
-    ) {
-      this.applyFillContent(this.iframe);
-    }
+    this.applyFillContent(this.iframe);
     const fontsArray = [];
     if (creativeMetaData.customStylesheets) {
       creativeMetaData.customStylesheets.forEach((s) => {
diff --git a/extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js b/extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js
index 8c305f0553a4..ea7050cc427f 100644
--- a/extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js
+++ b/extensions/amp-ad-network-adsense-impl/0.1/amp-ad-network-adsense-impl.js
@@ -44,7 +44,6 @@ import {
   maybeAppendErrorParameter,
 } from '../../../ads/google/a4a/utils';
 import {ResponsiveState} from './responsive-state';
-import {STICKY_AD_TRANSITION_EXP} from '../../../src/experiments/sticky-ad-transition-exp';
 import {Services} from '../../../src/services';
 import {
   addAmpExperimentIdToElement,
@@ -227,16 +226,7 @@ export class AmpAdNetworkAdsenseImpl extends AmpA4A {
    * @visibleForTesting
    */
   divertExperiments() {
-    const experimentInfoList = /** @type {!Array<!../../../src/experiments.ExperimentInfo>} */ ([
-      {
-        experimentId: STICKY_AD_TRANSITION_EXP.id,
-        isTrafficEligible: () => true,
-        branches: [
-          STICKY_AD_TRANSITION_EXP.control,
-          STICKY_AD_TRANSITION_EXP.experiment,
-        ],
-      },
-    ]);
+    const experimentInfoList = /** @type {!Array<!../../../src/experiments.ExperimentInfo>} */ ([]);
     const setExps = randomlySelectUnsetExperiments(
       this.win,
       experimentInfoList
diff --git a/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js b/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
index ef12b11370ca..b207c7325d7b 100644
--- a/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
+++ b/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
@@ -64,7 +64,6 @@ import {
   RefreshManager, // eslint-disable-line no-unused-vars
   getRefreshManager,
 } from '../../amp-a4a/0.1/refresh-manager';
-import {STICKY_AD_TRANSITION_EXP} from '../../../src/experiments/sticky-ad-transition-exp';
 import {SafeframeHostApi} from './safeframe-host';
 import {Services} from '../../../src/services';
 import {
@@ -107,7 +106,6 @@ import {
 } from '../../../src/experiments';
 import {getMode} from '../../../src/mode';
 import {getMultiSizeDimensions} from '../../../ads/google/utils';
-
 import {getOrCreateAdCid} from '../../../src/ad-cid';
 
 import {getPageLayoutBoxBlocking} from '../../../src/utils/page-layout-box';
@@ -485,14 +483,6 @@ export class AmpAdNetworkDoubleclickImpl extends AmpA4A {
         },
         branches: Object.values(IDLE_CWV_EXP_BRANCHES),
       },
-      {
-        experimentId: STICKY_AD_TRANSITION_EXP.id,
-        isTrafficEligible: () => true,
-        branches: [
-          STICKY_AD_TRANSITION_EXP.control,
-          STICKY_AD_TRANSITION_EXP.experiment,
-        ],
-      },
     ]);
     const setExps = this.randomlySelectUnsetExperiments_(experimentInfoList);
     Object.keys(setExps).forEach(
diff --git a/extensions/amp-ad/0.1/amp-ad-ui.js b/extensions/amp-ad/0.1/amp-ad-ui.js
index 66ba9d454feb..d49cbe22817e 100644
--- a/extensions/amp-ad/0.1/amp-ad-ui.js
+++ b/extensions/amp-ad/0.1/amp-ad-ui.js
@@ -14,39 +14,21 @@
  * limitations under the License.
  */
 
-import {
-  STICKY_AD_TRANSITION_EXP,
-  divertStickyAdTransition,
-} from '../../../src/experiments/sticky-ad-transition-exp';
 import {Services} from '../../../src/services';
 import {
   ancestorElementsByTag,
   createElementWithAttributes,
   removeElement,
 } from '../../../src/dom';
-import {devAssert} from '../../../src/log';
 import {dict} from '../../../src/utils/object';
-import {getExperimentBranch} from '../../../src/experiments';
 
 import {getAdContainer} from '../../../src/ad-helper';
 import {listen} from '../../../src/event-helper';
-import {setStyle, setStyles} from '../../../src/style';
+import {setStyles} from '../../../src/style';
 
 const STICKY_AD_MAX_SIZE_LIMIT = 0.2;
 const STICKY_AD_MAX_HEIGHT_LIMIT = 0.5;
 
-/**
- * Permissible sticky ad options.
- * @const @enum {string}
- */
-const StickyAdPositions = {
-  TOP: 'top',
-  BOTTOM: 'bottom',
-  BOTTOM_RIGHT: 'bottom-right',
-};
-
-const STICKY_AD_PROP = 'sticky';
-
 export class AmpAdUIHandler {
   /**
    * @param {!AMP.BaseElement} baseInstance
@@ -64,18 +46,10 @@ export class AmpAdUIHandler {
     this.containerElement_ = null;
 
     /**
-     * If this is a sticky ad unit, the sticky position option.
-     * @private {?StickyAdPositions}
+     * Whether this is a sticky ad unit.
+     * @private {boolean}
      */
-    this.stickyAdPosition_ = null;
-    if (this.element_.hasAttribute(STICKY_AD_PROP)) {
-      // TODO(powerivq@) Kargo is currently running an experiment using empty sticky attribute, so
-      // we default the position to bottom right. Remove this default afterwards.
-      this.stickyAdPosition_ =
-        this.element_.getAttribute(STICKY_AD_PROP) ||
-        StickyAdPositions.BOTTOM_RIGHT;
-      this.element_.setAttribute(STICKY_AD_PROP, this.stickyAdPosition_);
-    }
+    this.isStickyAd_ = this.element_.hasAttribute('sticky');
 
     /**
      * Whether the close button has been rendered for a sticky ad unit.
@@ -204,26 +178,22 @@ export class AmpAdUIHandler {
    * @return {boolean}
    */
   isStickyAd() {
-    return this.stickyAdPosition_ !== null;
+    return this.isStickyAd_;
   }
 
   /**
    * Initialize sticky ad related features
    */
   maybeInitStickyAd() {
-    if (this.isStickyAd()) {
-      setStyle(this.element_, 'visibility', 'visible');
-
-      if (this.stickyAdPosition_ == StickyAdPositions.BOTTOM) {
-        const paddingBar = this.doc_.createElement('amp-ad-sticky-padding');
-        this.element_.insertBefore(
-          paddingBar,
-          devAssert(
-            this.element_.firstChild,
-            'amp-ad should have been expanded.'
-          )
-        );
-      }
+    if (this.isStickyAd_) {
+      setStyles(this.element_, {
+        position: 'fixed',
+        bottom: '0',
+        right: '0',
+        visibility: 'visible',
+      });
+
+      this.element_.classList.add('i-amphtml-amp-ad-sticky-layout');
     }
   }
 
@@ -232,7 +202,7 @@ export class AmpAdUIHandler {
    * @return {Promise}
    */
   getScrollPromiseForStickyAd() {
-    if (this.isStickyAd()) {
+    if (this.isStickyAd_) {
       return new Promise((resolve) => {
         const unlisten = Services.viewportForDoc(
           this.element_.getAmpDoc()
@@ -249,7 +219,7 @@ export class AmpAdUIHandler {
    * When a sticky ad is shown, the close button should be rendered at the same time.
    */
   onResizeSuccess() {
-    if (this.isStickyAd() && !this.closeButtonRendered_) {
+    if (this.isStickyAd_ && !this.closeButtonRendered_) {
       this.addCloseButton_();
       this.closeButtonRendered_ = true;
     }
@@ -329,10 +299,10 @@ export class AmpAdUIHandler {
     }
 
     // Special case: for sticky ads, we enforce 20% size limit and 50% height limit
-    if (this.isStickyAd()) {
+    if (this.element_.hasAttribute('sticky')) {
       const viewport = this.baseInstance_.getViewport();
       if (
-        height * width >
+        newHeight * newWidth >
           STICKY_AD_MAX_SIZE_LIMIT *
             viewport.getHeight() *
             viewport.getWidth() ||
@@ -345,18 +315,7 @@ export class AmpAdUIHandler {
     return this.baseInstance_
       .attemptChangeSize(newHeight, newWidth, event)
       .then(
-        () => {
-          divertStickyAdTransition(this.baseInstance_.win);
-          if (
-            getExperimentBranch(
-              this.baseInstance_.win,
-              STICKY_AD_TRANSITION_EXP.id
-            ) === STICKY_AD_TRANSITION_EXP.experiment
-          ) {
-            this.setSize_(this.element_.querySelector('iframe'), height, width);
-          }
-          return resizeInfo;
-        },
+        () => resizeInfo,
         () => {
           resizeInfo.success = false;
           return resizeInfo;
@@ -364,19 +323,6 @@ export class AmpAdUIHandler {
       );
   }
 
-  /**
-   * Force set the dimensions for an element
-   * @param {Any} element
-   * @param {number} newHeight
-   * @param {number} newWidth
-   */
-  setSize_(element, newHeight, newWidth) {
-    setStyles(element, {
-      'height': `${newHeight}px`,
-      'width': `${newWidth}px`,
-    });
-  }
-
   /**
    * Clean up the listeners
    */
diff --git a/extensions/amp-ad/0.1/amp-ad-xorigin-iframe-handler.js b/extensions/amp-ad/0.1/amp-ad-xorigin-iframe-handler.js
index 0a83cb72c043..c422194fe3f6 100644
--- a/extensions/amp-ad/0.1/amp-ad-xorigin-iframe-handler.js
+++ b/extensions/amp-ad/0.1/amp-ad-xorigin-iframe-handler.js
@@ -100,6 +100,7 @@ export class AmpAdXOriginIframeHandler {
     devAssert(!this.iframe, 'multiple invocations of init without destroy!');
     this.iframe = iframe;
     this.iframe.setAttribute('scrolling', 'no');
+    this.baseInstance_.applyFillContent(this.iframe);
     const timer = Services.timerFor(this.baseInstance_.win);
 
     // Init the legacy observeInterection API service.
diff --git a/extensions/amp-ad/0.1/amp-ad.css b/extensions/amp-ad/0.1/amp-ad.css
index e3ff90dca1c9..e9f48c24fe0e 100644
--- a/extensions/amp-ad/0.1/amp-ad.css
+++ b/extensions/amp-ad/0.1/amp-ad.css
@@ -52,7 +52,6 @@ amp-embed iframe {
 
 amp-ad[sticky] {
   visibility: hidden;
-  align-items: center;
 }
 
 amp-ad[type='adsense'],
@@ -77,6 +76,10 @@ amp-ad[data-a4a-upgrade-type='amp-ad-network-doubleclick-impl'][height='fluid']
   width: 100% !important;
 }
 
+amp-ad.i-amphtml-amp-ad-sticky-layout {
+  overflow: visible !important;
+}
+
 amp-ad .amp-ad-close-button {
   position: absolute;
   visibility: visible;
@@ -116,42 +119,3 @@ amp-ad .amp-ad-close-button:before {
   right: -20px;
   left: 0;
 }
-
-amp-ad-sticky-padding {
-  display: block;
-  width: 100% !important;
-  background: #fff;
-  height: 4px;
-  max-height: 5px !important;
-  overflow-x: hidden;
-  overflow-y: hidden;
-  /** Must be above the dismiss button to cover bottom shadow */
-  z-index: 12;
-}
-
-amp-ad[sticky] {
-  z-index: 11;
-  position: fixed;
-  overflow: visible !important;
-  padding-bottom: env(safe-area-inset-bottom, 0px);
-  box-shadow: 0 0 5px 0 rgba(0, 0, 0, 0.2) !important;
-  display: flex;
-  flex-direction: column;
-}
-
-amp-ad[sticky='top'] {
-  width: 100% !important;
-  background: #fff;
-  top: 0;
-}
-
-amp-ad[sticky='bottom'] {
-  width: 100% !important;
-  background: #fff;
-  bottom: 0;
-}
-
-amp-ad[sticky='bottom-right'] {
-  bottom: 0;
-  right: 0;
-}
diff --git a/extensions/amp-ad/0.1/test/test-amp-ad-3p-impl.js b/extensions/amp-ad/0.1/test/test-amp-ad-3p-impl.js
index faa119d9933c..1d7f5cedf6b1 100644
--- a/extensions/amp-ad/0.1/test/test-amp-ad-3p-impl.js
+++ b/extensions/amp-ad/0.1/test/test-amp-ad-3p-impl.js
@@ -289,7 +289,7 @@ describes.realWin(
 
       describe('during layout', () => {
         it('sticky ad: should not layout w/o scroll', () => {
-          ad3p.uiHandler.stickyAdPosition_ = 'bottom';
+          ad3p.uiHandler.isStickyAd_ = true;
           expect(ad3p.xOriginIframeHandler_).to.be.null;
           const layoutPromise = ad3p.layoutCallback();
           return Promise.race([macroTask(), layoutPromise])
diff --git a/extensions/amp-ad/0.1/test/test-amp-ad-ui.js b/extensions/amp-ad/0.1/test/test-amp-ad-ui.js
index 2bf13c45f10d..256a19cc007f 100644
--- a/extensions/amp-ad/0.1/test/test-amp-ad-ui.js
+++ b/extensions/amp-ad/0.1/test/test-amp-ad-ui.js
@@ -245,7 +245,6 @@ describes.realWin(
             height: '50px',
           });
           env.win.document.body.appendChild(adElement);
-          env.sandbox.stub(uiHandler, 'setSize_');
           env.sandbox
             .stub(adImpl, 'attemptChangeSize')
             .callsFake((height, width) => {
@@ -263,7 +262,6 @@ describes.realWin(
         });
 
         it('should tolerate string input', () => {
-          env.sandbox.stub(uiHandler, 'setSize_');
           env.sandbox
             .stub(adImpl, 'attemptChangeSize')
             .callsFake((height, width) => {
@@ -327,7 +325,7 @@ describes.realWin(
     describe('sticky ads', () => {
       it('should render close buttons on render once', () => {
         expect(uiHandler.unlisteners_).to.be.empty;
-        uiHandler.stickyAdPosition_ = 'bottom';
+        uiHandler.isStickyAd_ = true;
         uiHandler.onResizeSuccess();
         expect(uiHandler.closeButtonRendered_).to.be.true;
         expect(uiHandler.unlisteners_.length).to.equal(1);
diff --git a/extensions/amp-story-auto-ads/0.1/amp-story-auto-ads.css b/extensions/amp-story-auto-ads/0.1/amp-story-auto-ads.css
index f81a1b88f3f4..f994386f174c 100644
--- a/extensions/amp-story-auto-ads/0.1/amp-story-auto-ads.css
+++ b/extensions/amp-story-auto-ads/0.1/amp-story-auto-ads.css
@@ -14,14 +14,9 @@
  * limitations under the License.
  */
 
-amp-ad[amp-story] iframe {
-  width: 100%;
-  height: 100%;
-}
-
-.i-amphtml-story-desktop-panels amp-story-page[i-amphtml-loading][ad] {
+ .i-amphtml-story-desktop-panels amp-story-page[i-amphtml-loading][ad] {
   /* Move below viewport so that ad preloads */
-  transform: scale(1) translateX(-100%) translateY(200%) !important;
+  transform: scale(1.0) translateX(-100%) translateY(200%) !important;
 }
 
 .i-amphtml-cta-container {
@@ -48,23 +43,21 @@ amp-story-page[xdomain-ad] .i-amphtml-glass-pane {
 }
 
 /* TODO(ccordry): refactor centering logic in amp-ad.css and remove this hack.  */
-amp-story-page amp-ad[data-a4a-upgrade-type='amp-ad-network-doubleclick-impl'],
-amp-story-page amp-ad[type='adsense'] {
+amp-story-page amp-ad[data-a4a-upgrade-type="amp-ad-network-doubleclick-impl"] > iframe,
+amp-story-page amp-ad[type="adsense"] > iframe {
   top: 0 !important;
   left: 0 !important;
   transform: translate(0) !important;
 }
 
 /* TODO(ccordry) allow advertisers to opt-in to fullscreen ads. */
-.i-amphtml-story-desktop-fullbleed
-  .i-amphtml-story-grid-template-fill
-  > amp-ad {
+.i-amphtml-story-desktop-fullbleed .i-amphtml-story-grid-template-fill > amp-ad > iframe {
   left: 50% !important;
   right: auto !important;
   margin: auto !important;
   min-height: 75vh !important;
   max-height: 75vh !important;
-  min-width: calc(3 / 5 * 75vh) !important;
-  max-width: calc(3 / 5 * 75vh) !important;
+  min-width: calc(3/5 * 75vh) !important;
+  max-width: calc(3/5 * 75vh) !important;
   transform: translateX(-50%) !important;
 }
diff --git a/package-lock.json b/package-lock.json
index 64cbb36a29bf..0998ad1d8461 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -936,9 +936,9 @@
       }
     },
     "@babel/parser": {
-      "version": "7.12.10",
-      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.12.10.tgz",
-      "integrity": "sha512-PJdRPwyoOqFAWfLytxrWwGrAxghCgh/yTNCYciOz8QgjflA7aZhECPZAa2VUedKg2+QMWkI0L9lynh2SNmNEgA==",
+      "version": "7.11.5",
+      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.11.5.tgz",
+      "integrity": "sha512-X9rD8qqm695vgmeaQ4fvz/o3+Wk4ZzQvSHkDBgpYKxpD4qTAUm88ZKtHkVqIOsYFFbIQ6wQYhC6q7pjqVK0E0Q==",
       "dev": true
     },
     "@babel/plugin-proposal-async-generator-functions": {
diff --git a/src/experiments/sticky-ad-transition-exp.js b/src/experiments/sticky-ad-transition-exp.js
deleted file mode 100644
index d9980177ded1..000000000000
--- a/src/experiments/sticky-ad-transition-exp.js
+++ /dev/null
@@ -1,42 +0,0 @@
-/**
- * Copyright 2020 The AMP HTML Authors. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS-IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import {randomlySelectUnsetExperiments} from '../experiments';
-
-/** @const @enum{string} */
-export const STICKY_AD_TRANSITION_EXP = {
-  id: 'sticky-ad-transition',
-  control: '21069722',
-  experiment: '21069723',
-};
-
-/**
- * Select exp vs control for sticky-ad-transition.
- * @param {!Window} win
- */
-export function divertStickyAdTransition(win) {
-  const expInfoList = /** @type {!Array<!../experiments.ExperimentInfo>} */ ([
-    {
-      experimentId: STICKY_AD_TRANSITION_EXP.id,
-      isTrafficEligible: () => true,
-      branches: [
-        STICKY_AD_TRANSITION_EXP.control,
-        STICKY_AD_TRANSITION_EXP.experiment,
-      ],
-    },
-  ]);
-  randomlySelectUnsetExperiments(win, expInfoList);
-}