Yes
I would first check the bass track's Event List for any events with a different MIDI channel than the rest (look in the location where the sound changes in the song).

If everything appears to be on the same channel, are there any Program Changes occurring?
The tricky part is that any of these events could happen on any track with MIDI.

The MIDI Monitor can help check all tracks at the location where the oddity occurs, but it takes a little getting used to.

It sounds like somewhere the bass notes either change MIDI channel (and thus use a different sound) or a Program Change is changing the sound assigned to that MIDI channel.
If you have (for sure) narrowed it down to a single track then the MIDI Monitor shouldn't be needed, just look on that track's Event List to track it down.


I do not work here, but the benefits are still awesome
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