[gonca]

Originally Posted by MrVideo

I don't remember seeing this trick mentioned. I'll try and remember if I run into this again. I've decided to go into a different direction and have decided not to deal with this file at all.

THD must have an interleaved ac3 core file for BD compliance.
MKV cannot store two interleaved tracks, so it splits them.
Stores them as a thd track and an ac3 track.
You are trying to encode a non compliant track.
Merge the thd and ac3 tracks together or re-encode an ac3 core into the thd track.
Or wait while BD_RB does it