Without a project file, it might be a long guessing game, as I have no idea what happens before you take an image.
If you have problems sharing (NDA), then ask the support.
Can you reproduce it on a sphere and share that?
Did you have a value larger than zero in the Offset?
Did you checked the “Set Roots” option, any improvement
Ah, just your quick comment helped…yea, it was the distance. I imagine it looks at the curve based on the last guides normal direction. So in a sharp curve of the head, it goes around the edge, which makes sense since it’s faked thickness.