Database changed externally when synchronised using Nexcloud

Currently I am using version 1.12-r5-test2848.

Making changes to the database works for the first time after adding it to Keepass2Android but when opening the database for a second time Keepass2Android always reports that the database has been changed externally although it isn't.
Even when removing the database and the local backup from the App and adding it again the behaviour remains the same.

These are the toasts popping up when unlocking the database:
Unlock database: Source file and cache are synchronized
Quick unlock: Files are in sync

This message appears when trying to save the database:

Merge changes?
The database file was changed externally. Do you want to load and save the changes before merging? Select no if you want to overwrite the external changes.
Cancel
No, overwrite
Yes, merge

If then I choose overwrite or merge I can make changes without problems, even after locking it is still fine but as soon as I close the database and re-open, it happens again.

This is a bit irritating because one can never be sure if there are indeed external changes.

Something I noticed as well but I am not sure if it is related. The toasts with the same messages sometimes have a blue and sometimes a red background.

I will gladly provide additional information if required.

No source file or test is identified in the report. Reproduce the repeated external-change warning with Keepass2Android 1.12-r5-test2848 using the described add, close, and reopen sequence, then trace the synchronization and save flow; done means the warning appears only when the database really changed externally.