What would cause this weird bearing wear?

I'm still at a loss for what was actually done when you put it together with those bearings. Or am I confused, and you didn;t put it together?

Anyway - it looks to me like too much oil clearance, probably a lot of tpaer on the journals, and oil wedge break down as a result. That lets the crank shift around in the block, and in some cases pushes it in one direction or another, creating the wear you see. I'd expect to see more copper is the crank was bent, and a lot more heat in the bearings.

In my opinion you should be using the right tools to measure the crank for taper, and crank and and the bearing bores to calculate clearance. Plastigage will not show taper. If you have oil clearance greater than .0025 I'd look at running a bearing to take up some of that. I generaly like to have between .002-.0025 on the mains.