Did anyone find a root cause and/or solution for this?
Mine is a little different but sounds very similar in that I would guess its more to do with a user group issue.
In my situation, I have a torrent-downloader with uid=99 and gid=100 that is creating folders/files with the drwxrwx--- permissions. Looks good because I am attempting to access from a user in the same "users" group (gid=100).. but I cannot access.
I have tried from both Win10 and Ubuntu with no success. Mapping to the /docker_downloads folder or to a "root folder" and signing in with the user2 name/pass makes no difference. I created another user, ensured it also was in gid=100 (it could not access), chown to the new user, but still cannot access from other users in the same group.
I ran the commands below to see the user/folder settings and it looks like it should work correct?
root@Tower:~# id nobody
uid=99(nobody) gid=100(users) groups=100(users)
root@Tower:~# id user2
uid=1001(user2) gid=100(users) groups=100(users)
root@Tower:~# ls -al /mnt/user/docker_downloads/
total 0
drwxrwxrwx+ 1 nobody users 28 Jul 23 13:55 ./
drwxrwxrwx+ 1 nobody users 76 Jul 22 13:37 ../
drwxrwxrwx+ 1 nobody users 122 Jun 1 14:00 xxxxx/
drwxrwxrwx+ 1 nobody users 266 Jul 23 13:31 xxxxxxxxxx/
drwxrwxrwx 1 nobody users 70 May 26 19:25 xxxxxx/
drwxrwxrwx 1 nobody users 796 Jul 10 12:25 xxxxxx/
drwxrwxrwx+ 1 nobody users 10 Jul 18 07:53 xxxxxx/
drwxrwx---+ 1 nobody users 244 Jul 23 11:29 test/
drwxrwxrwx 1 nobody users 176 Jul 2 12:07 xx-xxxxxx/
root@Tower:~# groups nobody
nobody : users
root@Tower:~# groups user2
user2 : users