I have been downloading midi (multiple track or type ) files from midi-hits.com and editing them in Cubasis on my 3rd Generation iPad nicely for several months.
Recently I am experiencing intermittent midi note event playback on any of the midi tracks - most noticabley on the bass and drum tracks.
I can see the note in the midi note event editor as the cursor passes over - silence!
The velocity information is good/normal.
If I reduce the number of midi tracks then consistent note playback returns.
I have had no problem, with as many as 18 midi tracks, to-date.
I use this setup to make money professionally…this is nontrivial to me…