diff --git a/packages/browser-utils/src/metrics/web-vitals/lib/initUnique.ts b/packages/browser-utils/src/metrics/web-vitals/lib/initUnique.ts
index 1eda48705b08..ef3e721dc09e 100644
--- a/packages/browser-utils/src/metrics/web-vitals/lib/initUnique.ts
+++ b/packages/browser-utils/src/metrics/web-vitals/lib/initUnique.ts
@@ -22,8 +22,16 @@ const instanceMap: WeakMap<object, unknown> = new WeakMap();
  * identity object was previously used.
  */
 export function initUnique<T>(identityObj: object, ClassObj: new () => T): T {
-  if (!instanceMap.get(identityObj)) {
-    instanceMap.set(identityObj, new ClassObj());
+  try {
+    if (!instanceMap.get(identityObj)) {
+      instanceMap.set(identityObj, new ClassObj());
+    }
+    return instanceMap.get(identityObj)! as T;
+  } catch (e) {
+    // --- START Sentry-custom code (try/catch wrapping) ---
+    // Fix for cases where identityObj is not a valid key for WeakMap (sometimes a problem in Safari)
+    // Just return a new instance without caching it in instanceMap
+    return new ClassObj();
   }
-  return instanceMap.get(identityObj)! as T;
+  // --- END Sentry-custom code ---
 }