After upgrading to 2.1.49, anki keeps forcing full sync of 400MB

after upgrading to 2.1.49 windows desktop yesterday, anki keeps asking me to update and then immediately says the decks on ankiweb and on my desktop are too different and need to force a full sync of 400MB (plenty of notes and media). anyway a moment later I press sync just to be sure that are synced and say it again. so far I re-downloaded the decks 3 or 4 times: waste of gigabytes and time.
Sometimes it gets stuck before this part, in a limbo like this one

from which it doesn’t get out.
what’s wrong?

maybe I solved, but keep it here if others find the same problem:.
I deleted all the other users
I disabled all addons
I deleted two decks I made recently (anyway I saved them for later) in order to lighten the upload/download, just before the update
after syncing (which was download from ankiweb), anki said that needs again syncing but this time I upload the whole collection from desktop anki. immediately after that I synced other devices (force sync downloading from ankiweb to devices). I checked again and so far everything seems fine
I guess the main point here is: after downloading from ankiweb immediately upload from desktop version
I tried, but didn’t work: unistalling, reintalling, re downloading the .exe file, restart computer.

It seems to be the same issue as treated here: Full sync required without comprehensible reason

It’s not the same issue.
As they stated in the link you provided:“All required full syncs had a comprehensible reason (updated scheduler, changes on decks etc.). But this one from today doesn’t.” and “I didn’t install any updates for maybe two weeks.”

But in my case it was because of the update to anki 2.1.49. I updated anki, and only then the problem arises

As someone else on that link said: “But once you either upload or download your collection, things should go back to normal.”

In my case I solved it, but only after doing both of those actions: downloading AND immediately after Uploading (as if the new version of desktop anki modified the whole collection and then it was that one that needed to be used on ankiweb and other devices)

Anyway thank you for signalling the other link: someone may have that other issue that only seems like mine.