diff --git a/packages/edit-site/src/components/global-styles/screen-revisions/get-revision-changes.js b/packages/edit-site/src/components/global-styles/screen-revisions/get-revision-changes.js
index 3e3b766d5f59d..f7eb8730a2e22 100644
--- a/packages/edit-site/src/components/global-styles/screen-revisions/get-revision-changes.js
+++ b/packages/edit-site/src/components/global-styles/screen-revisions/get-revision-changes.js
@@ -69,7 +69,7 @@ function getTranslation( key, blockNames ) {
 	}
 }
 
-const cache = new Map();
+const cache = new WeakMap();
 
 export function getRevisionChanges(
 	revision,