Hello Michael,
I deleted the point junction there, and...it works!

My rail curve is done as a freform going around the stone for the ring. I usually do half of the stone, then mrror the other half...reasons is that the cut is always a bit uneven, and instead of doing the whole perimeter by hand, resulting somehow less perfect, I mirror one half...the result is usually better.

Another trick learned to day.

I thank you very much.

Sincerely,
Rudy