Turns out it was a bent hanger. Thanks again for the help everyone.
It turns out this way SO OFTEN that I think a good rule of thumb is this: if you don't KNOW for a fact that the hanger is straight
relative to your frame* then the first thing to do is check the hanger, and adjust if needed, with the proper tool.
*Even a brand new hanger may not be straight relative to your frame, so the only way to guarantee a straight hanger is to check it.