Building roofs doesn't seem to work consistently

[frozen shoal]

I'm building a base, I have a complete floor foundation and walls, but I can only seem to attach roofing to the outside of my walls. At one point, I could build roofs on the inside of the walls but not anymore. The red circles that indicate attachment points only appear for the outside of walls and the roof tiles that I did manage to build within the walls do not allow me to attach additional roof tiles to them

[crude rain]

its random but i worked out the other day if u spin the roof parts around it sometimes fixes the issue