How did this animation error slide in Star Wars: The Clone Wars?!

I'm re-watching the entirety of Star Wars: The Clone Wars and I just noticed an animation/layering mistake, the clone trooper's visor is clipping through the two clone troopers and Fives walking by, and it even happens with the second clone trooper too, HOW CAN THEY MESS THIS UP?! #StarWarsTheCloneWars #AnimationError