Arms move weird when Waist motor changed

Changing the Upper Torso’s “Waist” Motor6D causes the upper arms to also move in an undesired way. Is this an intentional feature? if not, how do i fix it?

Image from Gyazo

is that only a c0 problem does it happen when you change c1?
mabey the arms motor6ds are the error if you have played around with these.
does it only happen when you change the x value or the other y.z also causes this issue