Did you create or purchase the sequence data? I ask because if you purchased the data, look at the event list and find the commands that cause the issue - could be events in the track. If you created the data then it should be easy to find the events causing this behavior... Either way the mystery is solved by looking at the data.

It has nothing whatever to do with RAM (?) or a defective unit, it is likely MIDI event data. So it is likely user error.

Nothing to do with RAM or whatever type of memory Montage uses. It turns out there were two bad MIDI events dealing with modulation in two of the tracks. I have isolated and fixed the problem. However, it was very interesting to see how the Montage was behaving because of those MIDI events:

All tracks would play fine from Pro Tools (using the Montage as the audio interface). The problem was noticeable once the MIDI file was exported to the Montage and played. Then, about six to seven of the tracks (tracks not containing the modulation MIDI events) would disappear. Thus, I would loose the sound those tracks were programmed to trigger. Additionally, rewinding the song would bring back all tracks letting me to believe that there was something wrong with the unit.

It's been quite a learning ride these last few days, and I have only scratched the surface...totally worth it though. The Montage sounds amazing! Once again, thanks for your input. Moreover, no one has answered my previous question: is there a way I can trigger specific parts of a song? In other words, is it possible to jump from one part of a song to another? I am interested in playing backing tracks non-linearly. I'd like to be able to jump back to a solo, as an example, if need be.

All tracks would play fine from Pro Tools (using the Montage as the audio interface). The problem was noticeable once the MIDI file was exported to the Montage and played. Then, about six to seven of the tracks (tracks not containing the modulation MIDI events) would disappear. Thus, I would loose the sound those tracks were programmed to trigger. Additionally, rewinding the song would bring back all tracks letting me to believe that there was something wrong with the unit.

This sounds like quite normal behavior when the instrument receives Bank Select and Program Change messages for Bank numbers it does not contain. There are 128 MSB and 128 LSB Bank Select numbers available in MIDI, meaning that there are literally thousands of possible Banks in any MIDI setup, the Montage will only respond to a small defined number of these possible Banks. If it receives a message for a Bank it does not have, a blank will occupy that Part/channel. Returning to the top of the song file can send a message that recalls the original status, so naturally all Parts are restored and noccupied. So there is a practical answer to what you are observing. Either way, the answer to the mystery will be inside the event data of the Midi file.

is there a way I can trigger specific parts of a song? In other words, is it possible to jump from one part of a song to another? I am interested in playing backing tracks non-linearly. I'd like to be able to jump back to a solo, as an example, if need be.

No, not using the Montage's built in Play/Rec function. It is a basic sketch recorder for capturing multi-Part Performances in one shot. And is designed to simply playback what you record, linearly. You would do better enlisting other methods to accomplish your goal. Here's a couple of ideas:

The Montage is a class compliant device, meaning there is no shortage of iOS device apps that would serve your needs. A simple USB cable and USB-to-Lightning adapter and you can connect to a world of recording and playback apps that would perhaps better serve your needs.

An alternate approach is to use the 10,000 Arpeggio Phrases on board to build your own accompaniment backing tracks. There are 8 arpeggiators, and 8 Arpeggio Selectable Sections so it is possible to put together your own custom musical sections.... Solo section, verses, choruses, bridge, interlude, etc. you can switch between these in reatime using the Montage front panel buttons. This approach could be used to great effect based on what you describe, in fact this would give you more control over things because you can change your mind about what section is playing at anytime.

Hope that helps.