Continuity mistake: When Bighead is summoned to the front, in the shot of him sitting from the front his cup is on the desk and he's not touching it. We cut to a side shot and he's suddenly holding it with his right hand.
Continuity mistake: Right before Meliodas punches Hendrickson, Meliodas holds the dagger in his left hand, but it switches to his right hand in the next shot. (00:22:06)