I've been using Joplin for few years now with the latest config as follows
Joplin 1.1.4 on Linux x86 (Elementary OS / Ubuntu 18.04.x)
Joplin 1.1.4 on Windows 10
Joplin 1.1.2 on Android 10
Sync is done over Webdav (underlying is Nextcloud 18.0.7 latest stable)
On Android, since a month now I already lost three times - and for no apparent reason - the config about Webdav sync and encryption. It's sounds like the config from Joplin app / config menu has been wiped-out however I cannot figure out how.
This morning for example I had to re-type in the config sync configuration and encryption keys, then it worked perfectly. How come the config menu is reset?
I'm trying to understand what is causing this issue, which I can't replicate, and I wonder if it's linked to sharing data with the app. Do you remember if you shared some text before it lost the settings?
I agree with @JackGruber here above: I tend to think this happens when you switch context (app) and this is why sharing text caused the issue. I installed v1.2.3 and I'll come back to this thread should the issue happen again (I just shared text with v1.2.3 and issue did not happen).
It's possible, I can't make sense of this part to be honest. This parameter solved certain multi-instance problems before (which, based on the log, seems to be what's happening here) so still worth a try. If if fixes the issue but breaks sharing, we can investigate at that point.
Removed current install. Installed 1.2.3 and setup sync/e2ee. Removed the "Welcome! (Mobile)" notebook. After sync and decrypt all is fine. Switched to Firefox and shared a link with Joplin (long press link, select Joplin). Joplin directly creates the "Welcome! (Mobile)" notebook and the settings are gone.
As I understand the issue is that a second instance (or perhaps activity? - but I'm not really familiar with this concept) of the app is created when sharing. And perhaps once two instances are running, it stays that way and strange things happen since the app is not designed for multiple instances accessing the db at the same time.
Do you have any suggestion on how we could fix this? For example is there any way, when sharing, to kill the current instance and create a new one?