Factory Mix Up

So I'm building the Blokees wave 7 cogged Bee and am like why won't his helmet go together that's odd. Oh, why does this back part of the head look different from the part on the instructions? Why don't the pegs match the ports? Why is it a ever so slightly different shade of yellow from the rest of the toy? I started to have hunch and investigated it to see that I was right. My set was package with the back head piece for the cogless Bee from wave 5. It's just a completely different part for a different toy.