Sync data loss, removes local changes and restores the server version

[Zvezdin]

⚠️ Before posting ⚠️

• This is a bug, not a question or an enhancement.
• I've searched for similar issues and didn't find a duplicate.
• I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
• I agree to follow Nextcloud's Code of Conduct.

Steps to reproduce

I have encountered a rare edge case issue, that I haven't found a way to reproduce. I am describing it here nonetheless as it leads to silent irrecoverable data loss. Hopefully other users will be able to chip in as well and we can pinpoint it.

Essentially I have an obsidian vault synced with the cloud on android. Everything's been working well for weeks. And now a day ago I create a new note, which gets synced successfully. Today I wrote a lot of new content on that note, without being connected to wifi so sync wasn't running. Afterwards, sync was running in the background every 15 min for a few hours, when I didn't touch any of the files. Then I open the note to see how yesterday's version has been restored (the last synced version), and all of today's changes were wiped.

Expected behaviour

New changes to be uploaded, or an error to be shown if something went wrong

Actual behaviour

New file changes were wiped, and the server version was restored

Android version

15

Device brand and model

Pixel 7

Stock or custom OS?

Stock

Nextcloud android app version

3.31.1

Nextcloud server version

30.0.6

Using a reverse proxy?

I don't know

Android logs

No response

Server error logs

Additional information

No response