Continuity mistake: Just after Sydney gets the book snatched from her by the guy in car, her hands stay near her body and don't move, but in the next shot her hands are thrown out to the side to add a surprised effect.
Bad Timing - S4-E22
Continuity mistake: At the end, the final shot of the boat with Aeryn & John crystalized shows that their pulse pistols are still there and intact. But when they are reconstituted at the beginning of "The Peacekeeper Wars", the pistols reappear on their belts for them to draw.
Continuity mistake: The 4 Space Rangers (Carlos, TJ, Cassie, Ashley) morph on the overhanging gangway, then jump off to the ground below. We see them hit the ground, and in the very next shot, they're right next to the Galaxy Rangers, and Andross, who are on the other side of the courtyard. There wasn't enough time for them to move that distance.
Continuity mistake: The professor knocks a hole in the side of a tunnel and hot water and steam gush out. The group is then distracted by a boulder traveling through the tunnel. After the boulder passes, there is no longer any steam or water gushing from the hole in the wall.
The Dark Heart of Friendship - S4-E25
Continuity mistake: Asuramon's faces keep changing positions. One shot his yellow/happiness face is on the left, the next it's on the right, and the same goes for his blue/sadness face.