I've had this problem, that when I want to set my BPM to 120, it keeps resetting back to 140, I've seen that a way to fix this is to delete BPM automation, but how do I do this?
One way is to right click in the bpm window, and select remove all song automation.
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Marcus Brigstocke
This happens when you have imported MIDI notes. MIDI has an inbuild BMP, that also (pr design!) works in LMMS.
That is known as Global-automation
GPS is correct, you disable all MIDI-info for one single controll, with rightclick and choose to remove global-automation