a three wall join not showing correctly in elevation

[Anonymous]

I have three walls joining in one corner. I have joined the two main walls and the third one I've cut with a void for the corner to look correct in plan views. For some reason this third wall joining the corner shows a white gap in elevation even though the third wall is joined to the corner without any gap. I've zoomed to the corner as close as you can and there´s not even a 0,1 mm gap in between the two. Why is this happening and how can I fix this so that the elevation looks correct?

[Avaris.]

Would it be possible to join the walls that are parallel instead of what you did now? So cut the wall coming in from the top.

[Anonymous]

No, that's how it's gotta be. The two walls that are now joined form the actual building interior (the walls have insulation etc) and the third that I've cut now is just an extension of the joining wall, sort of a wing. It doesn' t have insulation or anything so it's gotta be this wall I cut with the void.