Other mistake: Among the Titans groaning over Beast Boy's "brainfreeze" joke, we see XL Terrestrial, the pale-turquoise alien-looking guy with two antennae who can grow to large size. Again a mix-up of hero and villain identities, since XL was in the H.I.V.E. and the Brotherhood of Evil and should therefore not be among the young heroes. You will also see the Puppet King by Jericho.
Other mistake: When Red Star introduces himself, he takes off his parka with both hands. But as it drops to the ground, you can see the fingertips of his hands on top of the screen, standing completely still. This setup looks unnatural, as if he had suddenly taken off the parka with some telekinetic power.