I don’t know if it’s a design flaws or just the quality of the belt blade for my Murray riding lawn mower, but in the past it had slipped off many many times although I wasn’t the person whom driving it until a couple a months ago I tried new method to prevent it from slipping off.
What I did was just drive straight, don’t put on reverse, don’t change gear, don’t change height … just engage the blade and keep on driving. It work perfectly. Now I just need to change one of the front tire, $18 from amazon, but will be a pain since I have “tennis elbow”