diff --git a/src/contentScript/contentScript.ts b/src/contentScript/contentScript.ts
index b76d6f9324..732e48a544 100644
--- a/src/contentScript/contentScript.ts
+++ b/src/contentScript/contentScript.ts
@@ -15,9 +15,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+// IMPORTANT: do not import anything that has a transitive dependency of the messenger.
+// See for more information: https://github.com/pixiebrix/pixiebrix-extension/issues/4058
 import "./contentScript.scss";
 import { uuidv4 } from "@/types/helpers";
-import { onContextInvalidated } from "@/errors/contextInvalidated";
 import {
   isInstalledInThisSession,
   isReadyInThisDocument,
@@ -47,17 +48,12 @@ async function initContentScript() {
 
   setInstalledInThisSession();
 
-  // eslint-disable-next-line promise/prefer-await-to-then -- It's an unrelated event listener
-  void onContextInvalidated().then(() => {
-    console.debug("contentScript: invalidated", uuid);
-  });
-
   // Keeping the import separate ensures that no side effects are run until this point
   const { init } = await logPromiseDuration(
     "contentScript: imported", // "imported" timing includes the parsing of the file, which can take 500-1000ms
     import(/* webpackChunkName: "contentScriptCore" */ "./contentScriptCore")
   );
-  await init();
+  await init(uuid);
   setReadyInThisDocument(uuid);
 }
 
diff --git a/src/contentScript/contentScriptCore.ts b/src/contentScript/contentScriptCore.ts
index 74405e9233..7ea6272776 100644
--- a/src/contentScript/contentScriptCore.ts
+++ b/src/contentScript/contentScriptCore.ts
@@ -36,8 +36,10 @@ import { initPartnerIntegrations } from "@/contentScript/partnerIntegrations";
 import {
   isContextInvalidatedError,
   notifyContextInvalidated,
+  onContextInvalidated,
 } from "@/errors/contextInvalidated";
 import { uncaughtErrorHandlers } from "@/telemetry/reportUncaughtErrors";
+import { UUID } from "@/core";
 
 function ignoreContextInvalidatedErrors(
   errorEvent: ErrorEvent | PromiseRejectionEvent
@@ -51,7 +53,7 @@ function ignoreContextInvalidatedErrors(
 // Must come before the default handler for ignoring errors. Otherwise, this handler might not be run
 uncaughtErrorHandlers.unshift(ignoreContextInvalidatedErrors);
 
-export async function init(): Promise<void> {
+export async function init(uuid: UUID): Promise<void> {
   registerMessenger();
   registerExternalMessenger();
   registerBuiltinBlocks();
@@ -72,4 +74,11 @@ export async function init(): Promise<void> {
 
   // Let the partner page know
   initPartnerIntegrations();
+
+  // Put here instead of in the sync contentScript because contextInvalidated has a transitive dependency on the
+  // messenger (which causes a race on messenger initialization)
+  // eslint-disable-next-line promise/prefer-await-to-then -- It's an unrelated event listener
+  void onContextInvalidated().then(() => {
+    console.debug("contentScript: invalidated", uuid);
+  });
 }