diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.old.js b/packages/react-reconciler/src/ReactFiberBeginWork.old.js
index 3f5aab8a7441ee..c0557ec3fbbcad 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.old.js
@@ -910,7 +910,7 @@ function updateTracingMarkerComponent(
     }
   }
 
-  const instance = workInProgress.stateNode;
+  const instance: TracingMarkerInstance = workInProgress.stateNode;
   if (instance !== null) {
     pushMarkerInstance(workInProgress, instance);
   }
diff --git a/packages/react-reconciler/src/ReactFiberCommitWork.old.js b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
index e637de758d6f17..2777e4f537363e 100644
--- a/packages/react-reconciler/src/ReactFiberCommitWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberCommitWork.old.js
@@ -2829,15 +2829,20 @@ function commitPassiveMountOnFiber(
         }
 
         if (incompleteTransitions !== null) {
-          incompleteTransitions.forEach((pendingBoundaries, transition) => {
-            if (pendingBoundaries === null || pendingBoundaries.size === 0) {
-              addTransitionCompleteCallbackToPendingTransition({
-                transitionName: transition.name,
-                startTime: transition.startTime,
-              });
-              incompleteTransitions.delete(transition);
-            }
-          });
+          incompleteTransitions.forEach(
+            ({pendingSuspenseBoundaries}, transition) => {
+              if (
+                pendingSuspenseBoundaries === null ||
+                pendingSuspenseBoundaries.size === 0
+              ) {
+                addTransitionCompleteCallbackToPendingTransition({
+                  transitionName: transition.name,
+                  startTime: transition.startTime,
+                });
+                incompleteTransitions.delete(transition);
+              }
+            },
+          );
 
           if (incompleteTransitions.size === 0) {
             root.incompleteTransitions = null;
@@ -2908,6 +2913,10 @@ function commitPassiveMountOnFiber(
             const markerInstances = queue.markerInstances;
             if (markerInstances !== null) {
               markerInstances.forEach(markerInstance => {
+                if (markerInstance.pendingSuspenseBoundaries === null) {
+                  markerInstance.pendingSuspenseBoundaries = new Map();
+                }
+
                 const markerTransitions = markerInstance.transitions;
                 // There should only be a few tracing marker transitions because
                 // they should be only associated with the transition that
diff --git a/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.old.js b/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.old.js
index 54f06bdbe57b6a..dd7e542d4b252a 100644
--- a/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.old.js
+++ b/packages/react-reconciler/src/ReactFiberTracingMarkerComponent.old.js
@@ -117,36 +117,26 @@ export function pushRootMarkerInstance(workInProgress: Fiber): void {
     // marker does, so we can push it onto the marker instance stack
     const transitions = getWorkInProgressTransitions();
     const root = workInProgress.stateNode;
-    let incompleteTransitions = root.incompleteTransitions;
-    if (transitions !== null) {
-      // Create a mapping from transition to suspense boundaries
-      // We instantiate this lazily, only if transitions exist
-      if (incompleteTransitions === null) {
-        root.incompleteTransitions = incompleteTransitions = new Map();
-      }
 
+    if (transitions !== null) {
       transitions.forEach(transition => {
         // We need to create a new map here because we only have access to the
         // object instance in the commit phase
-        incompleteTransitions.set(transition, new Map());
-      });
-    }
-
-    if (incompleteTransitions === null) {
-      push(markerInstanceStack, null, workInProgress);
-    } else {
-      const markerInstances = [];
-      // For ever transition on the suspense boundary, we push the transition
-      // along with its map of pending suspense boundaries onto the marker
-      // instance stack.
-      incompleteTransitions.forEach((pendingSuspenseBoundaries, transition) => {
-        markerInstances.push({
+        root.incompleteTransitions.set(transition, {
           transitions: new Set([transition]),
-          pendingSuspenseBoundaries,
+          pendingSuspenseBoundaries: null,
         });
       });
-      push(markerInstanceStack, markerInstances, workInProgress);
     }
+
+    const markerInstances = [];
+    // For ever transition on the suspense boundary, we push the transition
+    // along with its map of pending suspense boundaries onto the marker
+    // instance stack.
+    root.incompleteTransitions.forEach(markerInstance => {
+      markerInstances.push(markerInstance);
+    });
+    push(markerInstanceStack, markerInstances, workInProgress);
   }
 }
 
diff --git a/packages/react-reconciler/src/ReactFiberWorkLoop.old.js b/packages/react-reconciler/src/ReactFiberWorkLoop.old.js
index bfddf20a89cdf9..647197e65f4904 100644
--- a/packages/react-reconciler/src/ReactFiberWorkLoop.old.js
+++ b/packages/react-reconciler/src/ReactFiberWorkLoop.old.js
@@ -1467,6 +1467,9 @@ export function popRenderLanes(fiber: Fiber) {
 function prepareFreshStack(root: FiberRoot, lanes: Lanes): Fiber {
   root.finishedWork = null;
   root.finishedLanes = NoLanes;
+  if (root.incompleteTransitions === null) {
+    root.incompleteTransitions = new Map();
+  }
 
   const timeoutHandle = root.timeoutHandle;
   if (timeoutHandle !== noTimeout) {