Fusion 360 issue - need some advice

I think this should be a simple 3d shape to cut I'm using Fusion 360 to cut a very simple flat triangle with a 72deg chamfer on 2 edges - the idea is to cut 5 which will then be stuck together to make a pentagon pyramid.

the whole thing is quite small (25 mm from base to point) and I'm using a 1mm flat bit - I went for a 3d contour and it generates to toolpaths except for 2 very annoying things.

I selected 3d contour and used the top and bottom contours to cut to and I have 2 problems

1/ the cut doesn't go all the way down to the bottom contour

2/ It won't cut along the vertical (short side) -I've tried using other modes with the same result

I'm clearly setting something wrong in using contour (I've only used it in 2d mode before) - can anyone help me with what I'm dong wrong ??

I tried earlier to submit this query but it didn't seem to work - apologies if I've posted twice by accident

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