There is another ongoing issue, which I would say looks very similar to this one, i.e. https://forum.syncthing.net/t/v1-18-1-started-afresh-trusted-untrusted-unexpected-items/17206. Both here and there the problem happens on a Linux system, and specifically a Debian-based one.
We have the logs, so I would now wait for one of the maintainers to have a look at them and see whether there is anything suspicious there.
Edit:
I have noticed that you have some encrypted files marked as .sync-conflict-*. How is this possible? The only situation that I can think of would be if the encrypted folder was shared with yet another device, but this time as non-encrypted, so the files would be treated as regular rather than encrypted. This doesn’t seem to be case here though.