Other mistake: After AD Skinner is finished being interviewed by the police, Mulder asks him about why he would employ the services of a prostitute. Skinner looks at him in shock and Mulder says "You didn't know she was a prostitute did you?" I find it hard to believe that at no point in the interview did the police not mention to Skinner the dead woman he woke up next to, after spending the night with her, was a prostitute.
Revealing mistake: As Dana Scully is examining the dead woman found in bed with Skinner, she observes a strange luminescent glow on the woman's nose and lips. It's apparent that this glow was added digitally; but the digital effect is "drifting" around the dead woman's face, seemingly out of sync with the video. Similar "drifting" digital effect problems are seen in other X-Files episodes.
Chosen answer: Yes.
Tailkinker ★