Hi Yenmonger, that one is pretty weird. Seems to be some difficulty in processing the vertical edge of the wedge, it would unfortunately take a lot of detailed effort to figure out exactly what is going wrong.

The pieces seem to be just a teeny tiny amount out of alignment, like on the order of 0.0000064 units away from each other. Something in the processing of this particular boolean is sensitive to that I guess though, because if I move the wedge away and then back again it seems to be ok, see attached file.

I don't see anything wrong with your geometry, it seems to be a case of edge merging getting confused with this particular case and this particular distance between the edges or something along those lines.

- Michael

Thanks for looking. I'll remember the move-back-and-forth trick for a future effort. In the meantime I just hacked up the surfaces and joined the pieces together. It was thankfully simple, all planes and such.