(at around 34 mins) Camera focus is lost for almost 6 seconds in this Scully closeup and remains lost until the camera pulls back to reveal the other characters.
Once again the state name Oregon is mispronounced, Mulder and CSM both say it like "Ore-gone". The correct pronunciation is "Ori-gun".
When Mulder answers the phone call from Billy Miles, the cord for David Duchovny's body microphone can be seen coming out of the top of his pants and going into his shirt behind his tie.
(at around 30 mins) The boom mic is visible in the rear window's reflection.