Good day,

I have a problem in one of my DiaLux evo Projects, that existing walls seemingly dissapear at random and new walls in other places appear by random. (Sometimes even some sort of roof layers like in the fist picture.)

Could someone help me understand where this is coming from and how to fix and avoid it in the future?

I have added some Pictures of some of the places where this is happening. The orange lines on the floor is where the walls should be (the lines of the rooms I created).

Thank you for any help.
(I am German, so answers in German would also be appreciated)