In any episode, watch the opening credits. Near the end of the credits, Ren and Louis are changing the channels on the TV and fighting over what to watch. When they take out lightsabers and accidentally hit the TV, right before it is hit you see that it is off! Why would they be changing channels on the TV if it is off?
Maybe whoever animated it didn't want to take more time to fix it if it actually was a mistake. Animation takes a LOOOONNGGG time. I make animations on Flash5 all the time and I hate having to go back and fix every frame for a stupid mistake. It really sucks.
This is a very good slipup! At first I thought that Louis could have been changing it on and off, but Ren is the last one to click the remote, and she wouldn't do that. Yep, this is just a slipup.
Did you ever think the T.V. could have broke BEFORE they started fighing with the "light sabers"? Ren probably changed it on the remote, that broke it, and then was mad at Louis so they started their fight. Then they broke it even worse. haha! didn't think of that did you???