In 'A Special Delivery,' a poster behind the clerk at the post office reads, "don't hug your kids with nuclear arms!"
In 'Real or Robots' Stu says to Chuckie that his mom and dad will pick him up in the morning. Chuckie's mom is later revealed to have died shortly after Chuckie's birth causing a minor continuity error.
In the end of 'Real or Robots', when Tommy and Chuckie wonder if Chaz is a robot, they both stare briefly at the camera out the window in shock when its storming.