Here is the media info from one of the files that is dropping audio
Format : Matroska
Format version : Version 2
File size : 35.0 GiB
Duration : 2h 20mn
Overall bit rate mode : Variable
Overall bit rate : 35.8 Mbps
Movie name :
Encoded date : UTC 2012-06-15 19:51:06
Writing application : MakeMKV v1.7.4 win(x64-release)
Writing library : libmakemkv v1.7.4 (1.2.0/1.1.0) win(x64-release)
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 2h 20mn
Bit rate mode : Variable
Bit rate : 32.0 Mbps
Maximum bit rate : 35.6 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.644
Stream size : 31.4 GiB (90%)
Language : English
Default : No
Forced : No
Audio #1
ID : 2
Format : DTS
Format/Info : Digital Theater Systems
Format profile : MA / Core
Codec ID : A_DTS
Duration : 2h 20mn
Bit rate mode : Variable
Bit rate : 1 510 Kbps
Channel(s) : 7 channels / 6 channels
Channel positions : Front: L C R, Side: L R, Back: C, LFE / Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 24 bits
Compression mode : Lossless / Lossy
Stream size : 1.48 GiB (4%)
Title : Lossless
Language : English
Default : Yes
Forced : No