My Gen3 has not had overheating yet, but it is still pretty cool in my garage (70F for upper 80s outside). The only overheating was the breaker, caused by the charger not being set up properly.
Mine was installed on a 50-amp breaker with #8 cable despite my having asked for 60 amp breaker and whatever cable gauge was necessary. The electrician, who allegedly installs Tesla wall chargers regularly (probably Gen 2s, though, which have switches for the breaker size settings), did not configure the charger for the smaller breaker size. The default config is apparently for 60 amp breaker. We have 2 M3SR+ cars (32 amp max draw), so we would never have noticed the difference. Then our daughter visited with her MX. About an hour after her arrival I started to wonder if the charger had been configured and asked, “Hey, how many amps are you pulling?” She checked her phone and responded, “48.” “Uh-oh” I went to the breaker panel and found the 50-amp breaker too warm. I had her throttle her charge current to 40 amps and used my phone to configure the charger that night.
If you get a Gen 3 charger installed on a breaker smaller than 60 amps, make sure you configure it or a MX, MS, or M3/Y LR or P might pop your breaker.