Other mistake: In the scene where Mulder and Scully are first visiting Darlene Morris, there is a split-second shot of Mulder examining residue on his fingers that is edited in between Mulder and Scully ascending the steps to the porch and knocking on the door. It's as if the sequence was initially longer with Mulder discovering a suspicious substance before he and Scully knocked on the door that was not completely edited out.
Other mistake: Eve 6 says that ordinary human beings have 46 chromosomes, while the Adams and the Eves have 56 chromosomes. This makes 10 additional chromosomes. However, Eve 6 also mentions that they have additional chromosomes number 4, 5, 12, 16, and 22 - only 5 additional chromosomes.
Other mistake: Being chased by Tooms underneath the escalator, Mulder climbs out of the manhole in front of the escalator, and hits the switch to activate the escalator. Tooms is then being dragged away from the manhole, but the direction of movement of the escalator below the floor would actually have dragged him towards the manhole where Mulder and Scully are.