Animation is overriding unused bones

Hi, I'm not sure if this is intended behaviour.
From what I gather on line, if I create a second animator layer and set it to override, then add some animations that only use a portion of the bones, only the bones animated in that layer should be overridden? Is this correct?

In my game I have added a layer for a hand wave, and added the animation that only records the arms movement. I have set it to override but the character no longer walks because the whole model is being overridden.

I understand I can create masks but that requires checking/unchecking every single bone or transform in the character.

Thanks

 

create avatar mask and assign to ur animator, or mask ur hand wave animation.
Thats the only solution.