Have had a lot of slide pins freeze up on calipers, but not to many pistons. In our area we do see failure of right rear first. Passenger side of the raod is where a lot of the dirt and salt settle in the winter.

Maybe that caliper got hot due to siezed pins or pads that were froze and maybe thats what seized the caliper. Hard to say, I would make sure the left side was good and free during replacement of the RR.

 

I actually had the exact thing happen to me about 2 months ago...and just today I noticed the caliper is squeaking excessively again, so it might be shot again. Has anyone found a solution to this problem??