I have my friend's Ford Falcon with over 350,000KM have its belt come off from the power steering pump, idler pulley, belt tensioner, power steering, crankshaft pulley, and AC compressor while it was in motion. But can one pulley with bearing play cause the serpentine belt to slip off?
It has over 350.000KM and the belt was never replaced. It's water pump had also started to leak when the belt came off.
Here's the video showing the belt and how it's supposed to go on or around the pulleys. I think it is a serpentine belt, not a V-belt.
Added (1). My guess is that the pulley with the bearing play from the water [ump had gone to an angle that caused the belt to jump right off the water pump pulley and some other pulleys. But why would the water pump develop a leak at the same time the belt jumped off the water pump?
Read more: https://fordnews.org/can-a-water-pump-pulley-with-bearing-play-cause-the.html