Yeah, me too, MacOS 10.12.5.
The midi exploration doesn’t show anything suspicious (to me). I used a midi to csv converter found online.
0, 0, Header, 1, 2, 480
1, 0, Start_track
1, 0, Title_t, "tempo track"
1, 0, Tempo, 555555
1, 0, Time_signature, 2, 1, 24, 8
1, 0, End_track
2, 0, Start_track
2, 0, Title_t, "Piano"
2, 0, Program_c, 0, 0
2, 0, Note_on_c, 0, 64, 70
2, 0, Note_on_c, 0, 48, 68
2, 0, Note_on_c, 0, 55, 67
2, 1, Note_on_c, 0, 72, 67
2, 816, Note_off_c, 0, 64, 0
2, 816, Note_off_c, 0, 48, 0
2, 816, Note_off_c, 0, 55, 0
2, 816, Note_off_c, 0, 72, 0
2, 958, Note_on_c, 0, 55, 64
etc.
This might be a bug. But I’ll let the Steinberg team confirm.
Let me know if you need anything from me to debug further.