Mergerfs & SMB single user issue

Union1 merges 3 drives. I have a share called media who's parent is union1. One user (A) can see everything in media (from windows10). The other user (B) can only see files in media which reside on "the 2nd" of the merged drives in union1. (also from windows10)

Disk 1 recently filled, so I changed the union1 policy from "existing path most freespace" to "most freespace". The most recent files added are on the 2nd disk. These are the only files user B can see, in a 'new path' on the most empty disk. User A behavior is normal, can see the entire union1 merged structure as expected.

Both users have the same privileges for the share. I've checked access from multiple windows machines - the problem follows the user. Inside union, everything is owned by root and assigned group is users. I've cleared ACLs and removed various unused shares, just to simplify. Removed and re-added union1... I removed and re-add user B. Nothing has improved.

Thoughts?

trapexit - any ideas? Maybe it's not smb and it's mergerfs related?

(moved from another forum branch)

Noticed something interesting. I wonder how the group is related... This is in the /srv directory. The first dev-disk-by... is the newest disk, a few weeks before I changed the union1 policy. The third item down dev-disk...3Ta is the disk in the union1 that filled up first. It's been in the machine since day 1. The one that ends 465f is union1. The files user B can see are from that first disk where the group is root...

I wonder, what is the proper owner and group assignment for my SMB-served data?

If nothing else but to help myself again in the future, I'll report this was a permissions issue. I had to reset the permissions through the "missing" drive, then the single user was able to see data from that drive again through union1 based share. And, I had to go back to the basics for setting user access rights.