I have updated my sites from Joomla 3.9.28 to 3.10.1 and then Seblod from 3.20.2 to 3.21.3.
In some content types I have a File (Upload) field which is repeated through a Field X.
After the updates, the Field X is not only no more storing data in the database, but also deleting their already existing values.
Now if we edit and save a content type which contains files uploaded by users, the stored values of the Field X are deleted and due to this also the content view broken.
It took me two days to realize on a production site, I can't reverse a backup after two production days.
Keep this in mind in case you have a similar scenario.
Any help will be appreciated.