Anyone can help with this problem diagnose?

Hello I have G36 and I jave problem with magazine feeding.

I have 2 "wind up gear" mags and 4 "push n load".

When I am trying to shoot full auto from both my wind up mags, approx every 5 BB will not shoot, then it will shoot 2-3 bullets at once and so on.

But when I am shooting full auto with my push and load mag, gun is working perfectly.

So are both of my "wind up" mags broken ? But I dont think they broke at the same time, they never fell and I used them on 7 actions with no problems.

Or there might be some issue with my gun? But why then it is working with push and load mags without any problems?

Thanks for help