Dexter's Laboratory - Hot and Cold
This slip-up is in the episode entitled "Gooey Aliens that Take Over your Mind" (That might not be the exact title, but it's something along those lines) in the part where Dexter is .thrown in the shower for aliens to take over his mind. In the shower, there is a hot water knob and a cold water knob. Then the camera changes position and there are two hot water knobs.
on 01-29-2004 and