Transmission

The thing is, inotify doesn't (correctly, if at all) work with cifs shares, at least using standard Linux implementation: https://lists.samba.org/archive/linux-cifs-client/2009-April/004318.html.

Thanks for providing the background on the technicalities of inotify with CIFS mounts, it was an ...

@PapaXris, are there any messages related to watchdir in daemon's log during startup (apart from those about adding found files)?

With 2.90+, I've added a "watch-dir-force-generic" boolean option support to the daemon. What you could do is add
...
"watch-dir-force-generic": true,
....
to ...

Is it possible to make the watch directory local to the host running transmission and access it over the network from the client? I.E. have your raspberry share the watch dir and then access it over the network from the system you are putting files in the watch dir. I ran that way for a while and ...

@PapaXris, are there any messages related to watchdir in daemon's log during startup (apart from those about adding found files)?

With 2.90+, I've added a "watch-dir-force-generic" boolean option support to the daemon. What you could do is add
...
"watch-dir-force-generic": true,
....
to ...

What version of Transmission are you using? There have been changes in this area in 2.90, so if you didn't try 2.90 or later yet please do.

Wanted to follow-up on this. I have a Linux Host that was using v2.82 and had the same issues with the watch folder over a network share using cifs protocol ...