Hi! I think the problem exist when the pitch of the roof is less then 4/12 and closer you have the skylight more chace you have that the shape of the first skylight overlap the next one.
So, less is the slope of the roof longer is projection of this entity.
The GDL Guru can fix that.
Thanks.
I think you can fix this issue by editing the edge of the hole in the roof. Use the appropriate pet palette option after clicking on the edge of the hole.
I tried to edit the roof but the problem is still there. I think the issue is with skilight itself, that subtracted a section of the subroof, like a SEO.