Sync issue: Firefox -> Other (Chrome, Android, iOS)

I'm using memex on multiple platforms and browsers. Sync seems to work pretty well between Chrome (Desktop), Android and iOS.

The only issue is Firefox (Desktop). It did some comprehensive testing...

Firefox receives updates from all other platforms (Android, iOS) and even Chrome.
But everything I add in Firefox is neither pushed to Chrome (running on the same Computer) nor to Android/iOS.

Now I have an inconsistent view/database between Firefox (my main browser) and the others.

I believe, it worked pretty good ~1month ago but stopped working with the latest updates. Hopefully, it can be fixed quickly.