Babylon 5 The Road Home: Commentary without audio track

[germansnowman]

This is my first time ripping a Blu-ray disc, so apologies for any rookie questions or mistakes. Most of the titles were converted perfectly, except for the last and largest one. This is supposedly a commentary by the director etc., but all I see is a double-length video track (the video is in fact included twice) without an audio track. Could this be a manufacturing defect, or is it an issue with MakeMKV?