When Ms. Bellum shows the Mayor the signal, her necklace disappears at one point.
In one moment, when Ms. Keane says to the girls that the Mayor called, her shirt is red.
When the Powerpuffs and Robin play with water, their swimsuits are at first one-piece with black stripes, but in close-ups of Bubbles and Buttercup have on a two-piece.
During the "Signal in the Sky" song in this episode, the signal that appears in the sky changes in angles from being viewed outside the window of the Girls' room that faces Townsville to behind the Girls' house and vice-versa.
During one scene the Girls are in their room, and the Mayor uses the signal when he could've used the hotline to contact the girls.
This was overall Ms. Bellum's idea.
At one scene, when Robin is sitting on living room couch, her pants are blue instead of red.
When Princess speaks one of her lines in the mini-mart, her mouth moves as if she is saying something else.