Skalp geometry dissapearing

I have an issue with Skalp in SU pro 2019. Skalp fills the sections just fine but when the file is saved some of the fill instantly disappears.

Before the file is saved, my screen looks like this.

Then I press Crtl + S (File->save)
After it is done saving (several seconds) some of the fill disappears, and my screen now looks like this:

This of course means that I cannot send the file to Layout.

Unable to help you with this, but the screenshots look the same to me.

take a look at the siding