Issue cutting smooth bottoms

So I am stumped. I have an X-Carve. I am cutting round holes in MDF. I have made several over this past year, no issues. Now I am having issues cutting flat. Instead of cutting a smooth bottom it’s leaving these ridges. I have tried a fresh bit; I have tried slowing the feed rate down, I have checked my belts, I have checked my eccentric nuts to insure the gantry isn’t lifting. Every hole I cut over different areas of the board the ridges are exactly the same shape in the exact same spot of every hole.
I am out of ideas to try???

I suspect that the flex inherent in the machine is causing that issue. Maybe try a bit like this:

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What is you depth per pass setting?
Are you using a down cut bit?
Provide as much details as possible for review.