Interpolation issue caused by invisible path

Hi there,
I’m encountering an interpolation issue.
I have this green and yellow path coming up where I’m drawing, a while checking into the shape order panel, the glyphs seems to have an extra outline that does not existe in what I’m currently drawing.
Has anybody encountered such issue ? How to fix this ?

Screen 165

I’ve come across this before, kind of ghost paths after removing/cutting bits. Georg and I discussed it on email before but we couldn’t establish exactly what caused it.

You can get rid of it by running Path > Tidy up Paths.