If you don't mind me asking, can you share some more info on this?
Did some searching around, and only found one [1] semi related issue from 2018. Is this the one you were referring to?
https://discourse.joplinapp.org/t/keep-original-notebook-on-...
I’m reasonably happy using Obsidian now, despite it being closed source and not supporting anything but proprietary sync mechanisms. I have no had any data loss issues with it.
https://discourse.joplinapp.org/t/keep-original-notebook-on-...
I just checked my log.txt file and I can't find mention of my master password. Maybe it is fixed?