The material is only .054 at the bottom of the pocket, and its
aluminum, so it makes sense that the cutter is easily lifting up the
material. And I also noticed that the shallow slot it leaves is
actually a little deeper along the two sides without clamps. The two
sides I am clamping down on have less of a slot.

I won't be able to clamp down all four sides since my table is only 3"
wide and the material I am cutting is just over 4". But I could use
some carpet tape to hold the peice down. I don't know if the foam
double sided tape would work since it has give to it. I could also
build a larger table to clamp to my existing table which would allow me
to clamp all four sides.

I think using the separate finish passes along with the tape should do
the trick. I'll experiment on the next one I make.

Thanks.