I have created TV shows with two added folders which are om two different volumes.
This worked great, until I discoverd that 1 folder is missing. The folder is still in the library configuration but all content is not visible in plex and is available on the nas.
Tried rescan, rebuild, removed it, added it again. Nothing works.
Do you use automated tools (software) to add to your media library?
I use software to capture OTA television programs.
I have to be very careful with their settings to make certain I don’t disturb the Synology’s permissions settings (which are very sensitive in DSM 7)
I say this because DSM might think the permissions are OK but on the files, down in the folders, got altered by the software which was capturing. DSM will not know this so the easiest solution / test is to re-apply permissions .
If that solves the problem then you have confirmation where it originates