The X-Files Season 7 Episode 20

When Anson (Kevin Weisman) is splashing through the mud puddle while invisible at 15:05, we should have been able to see the muddy water on his legs and feet. We should have also been able to see the dried mud on his legs and feet when he was lying dead on the side of the road at 15:45, as clothes or anything he is "wearing" does not turn invisible with him.

31:57 - Angry man walks away from cell bars, but at 31:59 when shot changes to Scully his arms are back on the bars.

In one of the last scenes in the episode "Fight Club". The person that was fighting Bert Zupanic in the ring was WWE superstar Rob Van Dam.

Despite the fact it makes for a neat little ending, showing Mulder & Scully's battle scars - as soon as the first set of twins come into the auditorium, everyone in the place starts to fight with each other.
Then when the second set arrive it gets worse, and yet during that scene there's no indication that either agent was affected. Mulder is surveying the scene and avoiding the violence going on around him. Scully is smiling to have introduced the second boxer guy. Surely if the effect of having these people in the same location was as automatic as we'd seen previously, everyone should have been fighting from the outset, including Mulder & Scully.

Why is Mr Saperstein in Mulder's office when Scully explains what has happened? Especially considering he doesn't have a visitors clip, and the fact he is smoking in the FBI headquarters.

Scully tells Burt that Betty lived in a blue house and later tells Mulder that she found Lulu, who lived in a pink house. Betty actually lived in the pink house and Lulu lived in the blue one.