Added a blu-ray I purchased onto Plex. The original has 2 audio streams. One with commentary and one without. When playing on the Plex server directly, I can select properly between them. When playing on my Roku, both audio streams contain commentary. I cannot view the film without commentary. I have re-ripped the blu-ray a few times. Same result every time. Any ideas?
Problem Solved. I just imported my uncompressed blu-ray rip mkv file into Plex and both audio streams play correctly. Of course, I now have an 11GB file instead of 1.7GB, but I can live with that.