So other then wonky legs and the fact that (im guessing) Chen wasnt in Bad Apple (havent actually seen it yet) what exactly is the error?

I think it is the legs. Leg bones should only bend that way if you're Sonic the Hedgehog.

And Chen was in Bad Apple, for all of a second.

Oh, I think I know. She's not got the ear-ring.

JakeBob said:
Oh, I think I know. She's not got the ear-ring.

It’s on her left ear, so it could be hidden by her hat.

Its her hands, they are on the wrong way round (the thumbs are on the wrong side).

Chen was in Bad Apple!!!
She appeared along with Ran, Tewi and Reisen.

alphamone said:
Its her hands, they are on the wrong way round (the thumbs are on the wrong side).

No they aren't.