Hello! I’m adding some info here in case anyone has this issue with their Powerfly. Mine did this too… shutting off over a bumpy section of trail every time I rode that spot. I re-adjusted the battery clips… that hold it in the frame and it stopped doing that. So maybe just loosen the bolts and...
I had an issue with my motor stuttering around 19mph and the display acting erratically… flipped the magnet on the hub from arching up to arching down and that resolved it.