Why impossibly switch to new poses in next shots in some cartoon shows?

Well it happens in former Cartoon Network shows like the Powerpuff Girls, Dexter's Laboratory, and the first season of Ed, Edd n Eddy, and one scene of one of its episodes in a later season. And current shows like Foster's Home for Imaginary Friends. Simply, at the end of one shot, a character is in a pose, and the next shot, he or she is in a different pose, without moving between shots. Or they can be in a totally different place in the next shot. It is completely impossible to move into a very different pose in less than a millisecond, even teleport into a different location in that sum of time. Remember the Ed boys' third episode, The Ed-Touchables? There's that scene where they are all trampled up and tangled together with Sarah. After that shot with her and Edd, the next shot shows everybody standing up without untangling between scenes. Sounds impossible?