Stretching arms

Hello people,

I have an issue with stretching arms on my character and can't find the reason for it. I hope you guys can help! 🙂

I created a puppet with 4 different outfits on 4 different layers („trikot“, „party“, „date“ and „weihnachten“). The weird thing is that it works on layer „trikot“ (left picture) but it doesn't work on the other layers (right picture as an example). I really don't know why it only works for one outfit because I did the same things on each layer with setting handles and everything that needs to be done.

Maybe one of you knows how to fix my problem. Here you can download it: https://we.tl/t-3wzELcEGKF