All For One - S3-E27
Continuity mistake: When Zane approaches Aster in front of the Slifer Red building, when he stops walking, he is standing right beside the edge of the wall next to him. In the next shot, he suddenly jumps forward a meter, and is past the edge of the wall. (00:11:30)
All For One - S3-E27
Other mistake: In the shot of the main characters falling through the portal back into the other dimension, Hassleberry cannot be seen among the group as they fall. Granted, Zane and Aster and Crowler and Echo wouldn't have been present in the shot as they were separate from the main group, but Hassleberry was with them so he should have been seen. (00:19:55)