Give me a sample of the one of the files which doesn’t play and I’ll check it.
I’ve not found anything valid which I can’t play.
“Some” is suspicious. One thing you must be careful of when dealing with Dolby – running out of inotify slots because the transcoder needs 1 slot per active stream
The default on pre 5.0 kernels is 8192
The default on 5.0 is 65536
Each directory monitored takes one slot (including the support structure)
Count up all directories being used. see if the limit exceeded
Here’s how-to increase if needed