Plex App and EAC3 issse (.tmp at the end)

I started having issues with videos with EAC3 audio, after A LOT of looking I found this forum post

This fixed my issue. Plex app was unable to remove the .tmp from the end of the folder. Once I did that it was able to use the codec and play videos with EAC3.

In the post it talks about adding a Plex user and group with ID 972. There is a service in the app called permissions, I assume this service is supposed to take care of all permissions but it appears to not?

In the “User and Group Configuration” of the app there is an ID. If I created a Plex user and group with 972 would I put that in there? I assume then, I would have to give 972 permissions in the ACL of the dataset?

Thanks for any help. Permissions in Linux are always messy for my brain.