Sigh. I’ll diagnose this in the morning, for now I’ll just sand it off but it always makes for a looser fit on the box when I do that. It was alleviated a bit when I reduced the feed 10% in CM4, so got to use that feature right away. May just take the settings back into GWizard and go a bit more conservative. Also possible the bit got bent, but since the ridges seem to stand proud of the cut deflection seems more likely.
I originally tuned this process on Maple and it’s possible the difference in hardness between maple and walnut mean my settings need tweaking, though I made some before without this issue so shrug. Probably going to give CC one more shot by making some of the cuts narrow pocket cuts instead of perimeter, after that might import this all info fusion360 where I can more easily setup a finishing pass.