Johannes KastlEdit: Solved, see reply in thread
More fun with Debian 13:
On two of my machines I noticed screen erroring out, as the permissions for /run/screen are wrong.
Seems this is caused by systemd-tmpfiles services failing to start. Unfortunately the journal for all the services are not helpful, as the only unusual thing I find is this:
```
Okt 12 15:34:58 XXX systemd[1]: /lib/systemd/system/systemd-tmpfiles-setup.service:26: Unknown key 'ImportCredential' in section [Service], ignoring.
```
Funnily enough, this file comes from the systemd package, not sure why it includes ImportCredential that systemd does not understand.
Digging further...