Mission Impossible Ghost Protocol and Dolby TrueHD

[dancjodanc]

I've decoded many movies using MKV with DTS MA, or Dolby TrueHD. Never a problem...till this movie. The TrueHD track is listed, I check it, and decode it. When I play the movie, it plays, but no sound. I have to switch to another audio track, which is just DD.
Never had this problem. Anyone else have a similar issue with this movie, or other Blu Ray's? Do I need to select or de-select something more specific?