Under 3 minute video. No way to show with screen shots.
To start with you’ll see an issue if you move while in design mode it will cause minor problem. Just exit design and restart it.
The problem is easy to duplicate. Create flooring / building on elevation. It presents a floor in all 3 dimensions until it hits something and then it will build on the lowest level it thinks it can achieve aka ground level or a tree. I used trees to get it to be only 1 block in thickness then cut down the offending tree once they started building.
End of video to show yes you can change PC’s names
Edit forgot here’s my dxdiag running latest nvidia beta drivers
DxDiag.txt (59.9 KB)
4 Likes
Can confirm this, and also add that the floor removal tool works the same way - and will flag existing floors for removal 
! Have to be very careful when building multi-storey structures ATM…
3 Likes
I can confirm this, too. I tried to build a floor on top of another floor to make some stairs and it gets easily in 3 dimensions.