Metal can flex/expand when heated. This can potentially cause the door latch to close harder. As long as it closes firmly and securely, the latch does not need to be fastened all the way.
That being said, if you would like to loosen the tension of the handle, it is possible to do so by loosening the bolt at the door handle’s pivot point. To do so, simply remove the four washers and nuts on the inside of the door which are holding insulation over the top of the handle’s bolt. When you are finished adjusting tension of the handle’s bolt, re-fasten the insulation to the inside of the door. Please do NOT loosen/adjust bolts while the arch is hot.