Chosen Solution
I have an iPhone 6 and home button was perfect. Put logic borad into a new housing which battery and charging port. The home button gets extremely hot now. This never happened previously in the old housing. Button has Touch ID and still all works. When I use a different button, it doesn’t get hot but I don’t want to lose Touch ID. I don’t know what else to do at this point.
It is likely something got damaged during replacement as heat indicates there’s a short, not on board level as it disappears replacing button. There’s not much one can do on such level without a very good magnification and proper tools, you can try and verify home button condition with a magnifying tools but fixing it, if possible, will require microsoldering skills or a replacement by Apple.
