^No reason the show would be cancelled for continuity reasons. Animated shows based on movies sometimes continue beyond the sequels and either ignore the inconsistencies or fold them into the show continuity without explanation. For instance, Ghostbusters 2 was pretty hard to reconcile with The Real Ghostbusters, but later seasons of that show drew on characters and elements from GB2 (notably making Louis Tully a regular and having him involved with Janine, even though previous seasons had played up Janine's romantic interest in Egon).
Kung Fu Panda: Legends of Awesomeness is kind of hard to reconcile with KFP2. In KFP2, Master Shifu has a limp from his injuries in the first movie, but in the show, which is evidently meant to come between the movies, he walks normally. And the show tends to revert Po to a less mature and competent level than he'd achieved by the end of the first film, at least some of the time. In any case, he's certainly less advanced in the show than at the start of the sequel, which could be explained if there's a large span of time between them, but there's a line in KFP2 where Po is told that the villain's invention could end kung fu and he says "But I just got kung fu," implying it hasn't been that long. And some of the episodes that focus on members of the Furious Five are sometimes tough to reconcile with what's been hinted about them in the movies. It's like most TV adaptations of movies in that it's only approximately consistent with them.
So far Dragons seems to have been more compatible with the movie, and even with the DVD specials (it uses some dragon species they introduced), but there's no guarantee that will continue. It could end up being an alternate take like most TV adaptations.
