Replacing Water Pump: Pulley Bolts Seized

I just did a water pump, belt, thermostat, control valve change on my 2008 Prius. I was getting a p1121 code so felt the control was the issue. I noticed some pink coming from the water pump so that also needed replacement. I purchase the car with 80k on it, and I put around 40k a year on it in mileage. I didn't change tensioner/pully since I test the bearing directly and it seems fine. Took for a test drive and everything went fine, so I buttoned everything down (torqued to spec) and drove it to SF, where the car overheated. I nursed it back about 30 miles to home thinking it was air in the system. It would run cool for 5minute/miles then the heater would blow hot and in 2 minutes car would overheat. Get home, no air in the system, radiator fan coming on etc, everything seemed fine, but radiator not hot, upper hose and lower hose were firm but no movement.

I went to check the belt tightness and to my horror realized the belt was gone. So much for my diagnosis abilities. Turns out the previous installer had put the bushing for the pully on backwards, and it had friction welded itself to the pulley. Since I had never replaced the pulley before I found it to be a strange contraption and only checked movement of the bearing itself (mistake). After putting the pully back on, it turned freely (at this point the spacer was acting as the bushing), but once I torqued it down, it wasn't rotating and I didn't check for rotation, but just assumed it was ok and drove off (bad mistake). I am assuming the belt eventually broke after about 30 miles (didn't smell any smoke).

So if you replace pully make sure the previous person didn't put the spacer in backwards and not tighten it down all the way. Don't think it won't work, my car went 90k with it in backwards.