Seems to be related to subtitles (fonts):
I do not have mkv without subtitles to test against, sorryThread 13 Crashed:
0 libSystem.B.dylib 0x00007fff8105fc00 strlen + 16
1 libSystem.B.dylib 0x00007fff810666f8 strdup + 28
2 libass.4.dylib 0x00000001166aeea0 fontconfig_init + 64
3 libass.4.dylib 0x00000001166b0521 ass_set_fonts + 145
4 liblibass_plugin.dylib 0x00000001166a4421 Create + 945
5 libvlccore.2.dylib 0x000000010007afc3 __module_need + 1139
6 libvlccore.2.dylib 0x0000000100043f50 CreateDecoder + 656
7 libvlccore.2.dylib 0x0000000100045961 input_DecoderNew + 145
8 libvlccore.2.dylib 0x000000010004c551 EsCreateDecoder + 65
9 libvlccore.2.dylib 0x000000010004c761 EsSelect + 401
10 libvlccore.2.dylib 0x000000010004ce67 EsOutSelect + 695
11 libvlccore.2.dylib 0x0000000100049f69 EsOutControl + 649
12 libvlccore.2.dylib 0x000000010004fc9b es_out_Control + 123
13 libvlccore.2.dylib 0x000000010004fd38 CmdExecuteControl + 136
14 libvlccore.2.dylib 0x000000010004ed2e Control + 3294
15 libvlccore.2.dylib 0x000000010005189b es_out_Control + 123
16 libvlccore.2.dylib 0x0000000100054be8 Init + 3816
17 libvlccore.2.dylib 0x0000000100051770 Run + 32
18 libvlccore.2.dylib 0x00000001000803fe thread_entry + 62
19 libSystem.B.dylib 0x00007fff81095f66 _pthread_start + 331
20 libSystem.B.dylib 0x00007fff81095e19 thread_start + 13