So this code is identical to what I posted here, with one hidden difference:
Instead of the default of zero for List Item ‘i’ input, you have modified that value to ten without making the change obvious… Not recommended! Better to use a text panel or integer slider.
The “holes on terminations” is a limitation of FilEdge (Fillet Edge). It often fails like that.
By the way, Z value of mid-points is not the only way to select edges. Not that it will help on this fail.