Aggrevating CSG bug - cannot union two completely on-grid parts

I have two parts that I arranged using only the default studio tools. My grid is set to 1/5th (0.2) of a stud, both wedges are sized (1.4,1.4,1.4), and I moved them around using purely the default dragger and R/T. I cannot union the two for the life of me and they give me a -9 error and move the the origin after the union fails. If I union them after they teleport to the origin the operation still fails. If I copy and paste them into a new place and attempt to union them, they fail again. This is making me tear my hair out because I’d never something this simple could throw an error.

Link to model.

The issue can be found here