diff --git a/.github/workflows/ci-workflow.yml b/.github/workflows/ci-workflow.yml
index 12eed48c50..879633918c 100644
--- a/.github/workflows/ci-workflow.yml
+++ b/.github/workflows/ci-workflow.yml
@@ -86,6 +86,7 @@ jobs:
         name: unit-tests-${{ matrix.node-version }}
         path: ./coverage/unit/lcov.info
     - name: Run ESM Unit Tests
+      if: matrix.node-version != '20.x'
       run: npm run unit:esm
     - name: Archive ESM Unit Test Coverage
       uses: actions/upload-artifact@v3
diff --git a/esm-loader.mjs b/esm-loader.mjs
index dd84ef9fa7..796e3fa955 100644
--- a/esm-loader.mjs
+++ b/esm-loader.mjs
@@ -3,12 +3,11 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import newrelic from './index.js'
-import shimmer from './lib/shimmer.js'
-import loggingModule from './lib/logger.js'
+//import newrelic from './index.js'
+//import shimmer from './lib/shimmer.js'
+//import loggingModule from './lib/logger.js'
 import NAMES from './lib/metrics/names.js'
 import semver from 'semver'
-import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 
 const isSupportedVersion = () => semver.gte(process.version, 'v16.12.0')
@@ -17,22 +16,41 @@ const isSupportedVersion = () => semver.gte(process.version, 'v16.12.0')
 const isFromEsmLoader = (context) =>
   context && context.parentURL && context.parentURL.includes('newrelic/esm-loader.mjs')
 
-const logger = loggingModule.child({ component: 'esm-loader' })
+//const logger = loggingModule.child({ component: 'esm-loader' })
 const esmShimPath = new URL('./lib/esm-shim.mjs', import.meta.url)
-const customEntryPoint = newrelic?.agent?.config?.api.esm.custom_instrumentation_entrypoint
-
-// Hook point within agent for customers to register their custom instrumentation.
-if (customEntryPoint) {
-  const resolvedEntryPoint = path.resolve(customEntryPoint)
-  logger.debug('Registering custom ESM instrumentation at %s', resolvedEntryPoint)
-  await import(resolvedEntryPoint)
-}
 
+// TODO: do this in globalPreload
+/*
 addESMSupportabilityMetrics(newrelic.agent)
+*/
 
 // exporting for testing purposes
 export const registeredSpecifiers = new Map()
 
+export function globalPreload() {
+  return `
+    const { createRequire } = getBuiltin('module')
+    const path = getBuiltin('path')
+    const { cwd } = getBuiltin('process')
+    const require = createRequire(cwd())
+    // load agent in main thread
+    const newrelic = require(cwd() + '/index.js')
+    debugger
+    const logger = require(cwd() + '/lib/logger.js')
+    // Have to do this in function as top level await does not work
+    /*
+    async function loadCustomInstrumentation() {
+      const customEntryPoint = newrelic?.agent?.config?.api.esm.custom_instrumentation_entrypoint
+      // Hook point within agent for customers to register their custom instrumentation.
+      if (customEntryPoint) {
+        const resolvedEntryPoint = path.resolve(customEntryPoint)
+        logger.debug('Registering custom ESM instrumentation at %s', resolvedEntryPoint)
+        await import(resolvedEntryPoint)
+      }
+    }*/
+  ` 
+}
+
 /**
  * Hook chain responsible for resolving a file URL for a given module specifier
  *
@@ -48,7 +66,7 @@ export const registeredSpecifiers = new Map()
  * @returns {Promise} Promise object representing the resolution of a given specifier
  */
 export async function resolve(specifier, context, nextResolve) {
-  if (!newrelic.agent || !isSupportedVersion() || isFromEsmLoader(context)) {
+  if (!isSupportedVersion() || isFromEsmLoader(context)) {
     return nextResolve(specifier, context, nextResolve)
   }
 
@@ -59,27 +77,37 @@ export async function resolve(specifier, context, nextResolve) {
    * duplicating the logic of the Node.js hook
    */
   const resolvedModule = await nextResolve(specifier, context, nextResolve)
-  const instrumentationName = shimmer.getInstrumentationNameFromModuleName(specifier)
-  const instrumentationDefinition = shimmer.registeredInstrumentations[instrumentationName]
-
+  const { pkgs, registerInstrumentation } = await import('./lib/loaded-instrumentation.js')
+  debugger
+  const instrumentationDefinition = pkgs[specifier]
   if (instrumentationDefinition) {
     const { url, format } = resolvedModule
-    logger.debug(`Instrumentation exists for ${specifier} ${format} package.`)
-
-    if (format === 'commonjs') {
+    //logger.debug(`Instrumentation exists for ${specifier} ${format} package.`)
+
+    if (registeredSpecifiers.get(url)) {
+      /*logger.debug(
+        `Instrumentation already registered for ${specifier} under ${fileURLToPath(
+          url
+        )}, skipping resolve hook...`
+      )*/
+    } else if (format === 'commonjs') {
       // ES Modules translate import statements into fully qualified filepaths, so we create a copy of our instrumentation under this filepath
       const instrumentationDefinitionCopy = [...instrumentationDefinition]
+
       instrumentationDefinitionCopy.forEach((copy) => {
         // Stripping the prefix is necessary because the code downstream gets this url without it
         copy.moduleName = fileURLToPath(url)
 
         // Added to keep our Supportability metrics from exploding/including customer info via full filepath
         copy.specifier = specifier
-        shimmer.registerInstrumentation(copy)
-        logger.debug(
+        registerInstrumentation(copy)
+        /*logger.debug(
           `Registered CommonJS instrumentation for ${specifier} under ${copy.moduleName}`
-        )
+        )*/
       })
+
+      // Keep track of what we've registered so we don't double register (see: https://github.com/newrelic/node-newrelic/issues/1646)
+      registeredSpecifiers.set(url, specifier)
     } else if (format === 'module') {
       registeredSpecifiers.set(url, specifier)
       const modifiedUrl = new URL(url)
@@ -109,7 +137,7 @@ export async function resolve(specifier, context, nextResolve) {
  * @returns {Promise} Promise object representing the load of a given url
  */
 export async function load(url, context, nextLoad) {
-  if (!newrelic.agent || !isSupportedVersion()) {
+  if (!isSupportedVersion()) {
     return nextLoad(url, context, nextLoad)
   }
 
diff --git a/esm-preload.js b/esm-preload.js
new file mode 100644
index 0000000000..9ed77fddb1
--- /dev/null
+++ b/esm-preload.js
@@ -0,0 +1,4 @@
+function preload() {
+  require('./index')
+}
+module.exports = preload()
diff --git a/lib/loaded-instrumentation.js b/lib/loaded-instrumentation.js
new file mode 100644
index 0000000000..751d1e1579
--- /dev/null
+++ b/lib/loaded-instrumentation.js
@@ -0,0 +1,44 @@
+const pkgs = Object.create(null)
+function registerInstrumentation(opts) {
+  if (!hasValidRegisterOptions(opts)) {
+    return
+  }
+
+  const registeredInstrumentation = pkgs[opts.moduleName]
+
+  if (!registeredInstrumentation) {
+    pkgs[opts.moduleName] = []
+  }
+
+  pkgs[opts.moduleName].push({ ...opts })
+}
+
+function hasValidRegisterOptions(opts) {
+  if (!opts) {
+    //logger.warn('Instrumentation registration failed, no options provided')
+    return false
+  }
+
+  if (!opts.moduleName) {
+    //logger.warn(`Instrumentation registration failed, 'moduleName' not provided`)
+    return false
+  }
+
+  if (!opts.onRequire && !opts.onResolved) {
+    /*logger.warn(
+      'Instrumentation registration for %s failed, no require hooks provided.',
+      opts.moduleName
+    )
+    */
+
+    return false
+  }
+
+  return true
+}
+
+
+module.exports = {
+  pkgs,
+  registerInstrumentation
+}
diff --git a/lib/shimmer.js b/lib/shimmer.js
index af876594bb..94830a2a9b 100644
--- a/lib/shimmer.js
+++ b/lib/shimmer.js
@@ -17,6 +17,7 @@ const NAMES = require('./metrics/names')
 const symbols = require('./symbols')
 
 const MODULE_TYPE = shims.constants.MODULE_TYPE
+const loadedInstrumentations = require('./loaded-instrumentation')
 
 const CORE_INSTRUMENTATION = {
   child_process: {
@@ -430,21 +431,8 @@ const shimmer = (module.exports = {
     shimmer.registerThirdPartyInstrumentation(agent)
   },
 
-  registerInstrumentation: function registerInstrumentation(opts) {
-    if (!hasValidRegisterOptions(opts)) {
-      return
-    }
-
-    const registeredInstrumentation = shimmer.registeredInstrumentations[opts.moduleName]
-
-    if (!registeredInstrumentation) {
-      shimmer.registeredInstrumentations[opts.moduleName] = []
-    }
-
-    shimmer.registeredInstrumentations[opts.moduleName].push({ ...opts })
-  },
-
-  registeredInstrumentations: Object.create(null),
+  registerInstrumentation: loadedInstrumentations.registerInstrumentation, 
+  registeredInstrumentations: loadedInstrumentations.pkgs, 
 
   /**
    * NOT FOR USE IN PRODUCTION CODE
@@ -702,29 +690,6 @@ function _instrumentOnResolved(agent, moduleName, resolvedFilepath) {
   })
 }
 
-function hasValidRegisterOptions(opts) {
-  if (!opts) {
-    logger.warn('Instrumentation registration failed, no options provided')
-    return false
-  }
-
-  if (!opts.moduleName) {
-    logger.warn(`Instrumentation registration failed, 'moduleName' not provided`)
-    return false
-  }
-
-  if (!opts.onRequire && !opts.onResolved) {
-    logger.warn(
-      'Instrumentation registration for %s failed, no require hooks provided.',
-      opts.moduleName
-    )
-
-    return false
-  }
-
-  return true
-}
-
 /**
  * Adds metrics to indicate instrumentation was used for a particular module and
  * what major version the module was at, if possible.
diff --git a/test/integration/logger-test-case/hello.js b/test/integration/logger-test-case/hello.js
index 02f7bf0ef9..7b285c1507 100644
--- a/test/integration/logger-test-case/hello.js
+++ b/test/integration/logger-test-case/hello.js
@@ -5,7 +5,9 @@
 
 'use strict'
 
+debugger
 const newrelic = require('../../../index.js')
+const express = require('express')
 
 function greeter(name) {
   return `Hello ${name}`
diff --git a/test/integration/logger-test-case/package.json b/test/integration/logger-test-case/package.json
new file mode 100644
index 0000000000..f4524b250d
--- /dev/null
+++ b/test/integration/logger-test-case/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "logger-test-case",
+  "version": "1.0.0",
+  "description": "",
+  "main": "hello.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "express": "^4.18.2"
+  }
+}