Talk:List of crossovers/@comment-30517056-20170303212645/@comment-29163869-20170304181222

You are correct, they weren't officially added to the series until the end of Season 5 (when the first of them actually aired during Season 4). I remember when they were first airing, they were always listed "officially" as Jimmy Neutron episodes. I remember that for some reason, probably because it struck me as odd, as I didn't understand the concept of production order and such at that age.