Uneven bow pad...trolling motor crooked

I've had to shim every trolling motor I've installed on my 2018 Z520C. Today, I was attempting to install a new Garmin Force and ended up having to add numerous SS washers on one side to even it out. I thought it may have been the rubber bow mat and removed some of it. When I looked at it, the fiber-glassed bow area where you mount the TM is uneven. I assume it came for the factory that way since it's never been wrecked or damaged. Now I have half the pad off and can only think of shimming it once again or adding a spacer like the Ashmore one, but I think it would still need that shimmed. Any ideas or thoughts? Anyone run into this?