Doesn't work with unionfs or mergerfs

Just letting you guys know the scan stops after a few additions to the library when using unionfs or mergerfs.
It only works when you’ve added the source mounted drive.

I would suggest that you need to read the mergerfs docs and wiki closely. The reason being there are several things you have to set for things to work correctly. I am using mergerfs with 20+TB and have no issue. I also use it with Sonarr, Radarr, Lidarr, Bazarr and other similar stuff.