Can an unseated pin head interfere with a hinge pin?

Yes, an unseated pin head will interfere with a door hinge pin. Door hinges must lay flat up against a door frame. A hinge pin holds the 2 metal parts of the door hinge together. The pin head is always bigger than the hole that it goes inside, in order to prevent it from falling out. Therefore if the pin head part of the hinge pin isn’t properly seated within the hole, the door hinge will not work properly. It will also not allow the door hinge pin to go all the way into the door hinge. This will cause the hinge to be weaker that it should be.