No it’s not something you did. It seems a behaviour of systemd on Debian Bookworm. We already had a similar case and we are looking for possibilities to work around. For time being, don’t use drive manager as this will reset the mount option
It is slightly different than in the other case. There the EnvironmentFile= directive in the [Service] block was the issue, not causing the systemd.automount to trigger. Here it is AssertPathExists= in the [Unit] block. However, similarly when checking whether something exist, the automount should be triggered, as it is when doing e.g. ls /mnt/dietpi_userdata/navidrome or stat /mnt/dietpi_userdata/navidrome.
Here we cannot add a touch command like in the other case. We added AssertPathExists= since ReadWritePaths= is used as well. And if the latter fails as the directory “really” does not exist, it throws a very confusing error message which does not give a clue unless you know what it is about. So we added AssertPathExists= which is checked first. However, it seems to not show that much more information either? At least the word “Assertion” in the error message can be found in the systemd service.
The question is now whether just removing AssertPathExists= works, or whether ReadWritePaths= fails as well and does not trigger the automount.