Hey, it could've been one of those "handyman special" type job... which reminds me of another situation I found while doing a service change - a handyman installed a 3,000W heater in each bedroom and then slapped in a 30A breaker because the 20A one kept tripping. Talk about a fire waiting to happen.
In this case I did replaced the other two thermostats in bedrooms because they also showed signs of overheating. Vents were not obstructed by anything.
