Thunderbird wants to submit changes to Nexcloud CalDAV server on every launch

This is really weird, because TB shouldn’t have made any changes whilst not running. I think it’s erroneously asking to submit its older cached state of the server to the server instead of merely pulling from the server, despite there being no user made changes locally.

I don’t want it to do this, because I’m scared that one day I’ll eventually click “Submit” instead of “Discard”.