I’ve had an XR and have had 2 falls from it teetering out. I was going 17mph and hit a slight incline, it dropped me like a rock. The other time I left at 100% and it died after 2 miles I felt the pushback and then it immediately sent me to the ground and then it died, at only 12mph.
Neither case is acceptable, I wasn’t exactly pushing it to it’s limits either.