In most episodes, the Decepticon symbol is drawn incorrectly. It has three "spikes" jutting out of its middle-upper section, when there should only be two. This is probably due to faulty animation models, and is thus a legitimate error. Only on a handful of occasions are the symbols drawn the right way.
The second title sequence of Season 3 contains a number of notable animation errors. When the Sharkticon swims towards the screen and opens its mouth, it suddenly turns upside-down for a couple of frames. And in the last shot of the sequence, Ultra Magnus' head is colored entirely blue (his face should be gray), and Kup is drawn with Springer's head. These errors are easy to spot, since the appear in almost every episode of the season.
Animation errors can be found in each and every episode, and some of these are quite noticeable. Characters are colored differently from shot to shot at times, robots that should be dead appear randomly, and sometimes, you can see the same character twice in the same shot. Another issue is the misplacing of animation cels, which resulted in characters appearing to be small/gigantic, and in some instances, full limbs and other body parts are missing.