I set my tempo to 128 bpm, save song, turn off, turn on and tempo is at 120 bpm, when i increment to next part tempo is back to 128 bpm.
This behaviour happens in both part and global tempo mode.
I did a factory reset the other day and then I noticed this behaviour.
Edit to add: This behaviour only happens when part is 00 and turned off and on again, but doesn't happen with part 01 or 02.
Version 2.14