Sony released firmware 1.01 to improve the overheating warning function today. There was some speculation that the warning came from the SD card in the second SD card slot, but I was never able to reproduce it on my camera with the 4 different card types I tried. Hopefully, this resolves the issue for everyone. The firmware isn’t specific, but it will be interesting to see what the users that first reported overheating experience after the patch.
Maybe Sony increased the thermal limitations due to a sensor not being accurate enough or slightly miss placed internally. It looks like we will never know for sure what the issue was if this patch works for everyone affected.
You can download firmware 1.01 here. (Temporarily Pulled)