Other mistake: Padget hands over one page of his book to his imagined character who is invisible to anyone else except him. Therefore, the page should hover in the air for an external observer. However, Scully watches his apartment on a monitor and notices nothing strange. (00:38:05)
Plot hole: Big Mike was attacked by the creature, because his bulb was broken just for a couple of seconds. It would mean that even if something like this happened to somebody else by accident, this person would also be killed by the creature. That would drastically increase the kill rate in the community. (00:16:15)
Suggested correction: That was the whole point of the creature, to enforce the HOA rules so that no violations occurred, even by accident. Although prior to the attack, Gene Gogolak describes Big Mike as a weak link that had to be dealt with, so the bulb was just an excuse to attack him.
Continuity mistake: At The Beginning of the scene in his office, in the front shot Skinner wipes his glasses in his hands, but in the following back shot he's wearing them. (00:12:25)
Factual error: When Mulder is walking out of the cabin in Spender's uniform, the soldiers try to stop him. This is impossible since he is an officer (a lieutenant judging from the shoulder-straps) and they are privates, so they cannot give him orders. The only thing they can do in this situation is to salute him. (00:08:40)
