15th Oct 2011
Day 4: 12:00 P.M.-1:00 P.M. - S4-E6
Revealing mistake: During the rescue, a few shots after SecDef Heller announces to Jack that he's also out of ammo, you see a shot of the bullet-riddled car taking a few more bullets. The new bullet holes obviously fade in.
10th Oct 2011
Day 4: 2:00 P.M.-3:00 P.M. - S4-E8
Continuity mistake: When Curtis Manning is chasing Mary-Ann Taylor out of CTU, you see Mary-Ann exiting through a solid grey door marked by an EXIT sign in a wall which looks like concrete. As she passes through the door, you can see sunlight on her from almost directly above. In the next shot Mary-Ann is seen exiting through a glass door in a wall of glass panels. Unless there is a section of CTU's roof missing, the room she exits from in the second shot is not the room she exits to a few seconds earlier in the first shot.
4th Sep 2011
Day 4: 2:00 P.M.-3:00 P.M. - S4-E8
Factual error: When Edgar proves that Mary-Ann Taylor framed Sarah to be the rat in CTU, he claims that she remotely took control of her computer by sending the signal over "a plain old AC power line." This is not possible, unless the computers were equipped with special hardware to separate the AC from the signal. If they were, this traffic would have been observed by James Heller's assistant.