LrC: edits on synced images in Lr Mobile sync to web but not to catalogue

I like to do base edits on my pictures on my commute, have done so for years and it has always worked flawlessly. For this I add the photos on LrC on Windows, sync the collections I'm currently working on to the cloud, then work on them on Lr Mobile.

I make sure that I give time for the photos to sync before moving to the next photo and ensure that the sync is done before closing the app.

I can see all the edits that I have done on mobile on the web version, but they always stop syncing back to LrC after a couple images and I have to rebuild the cloud sync for them to come into LrC. I have also tried it from the other side and deleted the online Lightroom library. The result is the same: sync stopps after a couple images and I have to rebuild the sync.

What's happening here? This doens't make any sense at all - after all the Mobile to cloud connection is the one that is potentially unstable, yet this works.

It's extremely frustrating because I spend more time troubleshooting this functionality than I am saving with editing on my commute.