I faced with this issue for calendar. I had my calendar synced with Nextcloud. In one of the calendars, I added an event on my phone (which uses Persian language) and set reminder. Thereafter, I had sync issue.
Today I looked at the .ics file and saw this:
You can clearly see on TRIGGER line, there are Persian numbers.
I manually edited the file and made a new calendar on Nextcloud. It is working fine now.
Just the point is title or description shouldn’t be modified. Only those lines should be modified which use number for some calculation.
Will 126.96.36.199 be released on F-Droid? I’ve started experiencing this same exception yesterday with a FastMail calendar on 3.2.1. (Wouldn’t surprise me if it also had to do with a Google Meet event, since I have a couple of those.)
I undestand how to reproduce the problem.
I uninstalled Davx5 and then reinstalled it.
The synchronization was going perfectly.
No more error message.
I returned to my google calendar.
Events for which I have been invited are considered “unanswered”. I went on one of them and then I “accepted”. Immediately, the synchronization error message reappeared.