Strange/unexpected results with odd/even sided polygons

The part I am making is based on a 7-sided polygon with filleted corners. To facilitate  3D printing I have made cutouts in the bottom that look like this:
Notice that there is one row of missing cutouts.

If I change the number of polygon sides to 8 the result looks like this:

Note that there are no missing rows with 8 sides. I've tried all the numbers from 3 to 12 and in general an even-number of sides results in no missing rows, but an odd number of sides has a missing row. And for # sides 10 - 12 there are 2 missing rows.

I tried all the options for the Offset object's Corners variable which is use to make the solid outside wall, but this has no effect. I also tried rotating the cutouts a little and a lot, changing their size, height, etc., but this had no effect either. So I'm stuck on how to eliminate the missing row of cutouts.

I realize this is a more or less cosmetic problem (no one will see the bottom of the printed part unless they pick it up), but I'd like to get it fixed before I publish the final design.  The attached GH file has all the components used to make these images.