It's been only three days and I realised #Asus6Z camera heats up like crazy. Please let me know if you people are facing the same issue or this is a defect in the camera.
I had the same problem, phone always very hot under minimal usage but since i updated to version 191 the phone doesn’t heat like before. In my case the problem was solved with the update.
To add to VS-KR comment. If you record in 4K, then it will get hot and if you record in 4K with EIS, then it will get VERY hot but it's by design, so no need to worry.