Hi there!
I am a bit new to Ubuntu but I seem to have found myself in the same situation. Did you ever find a solution to this? I created a test file /movie which contains the following permissions:
drwxr-xr-x 2 root root 0 Dec 18 16:44 movie
From Unraid, this file should be giving all users read, write, and execute permissions:
drwxrwxrwx+ 1 nobody users 50 Dec 18 11:44 movie/
From what it looks like, it has something to do with Ubuntu not seeing its permissions the same as Unraid.