During placement of new buildings it is possible to place buildings in such a manner that visible grey borders overlap, existing buildings have also gained new bigger borders that overlap. (Screenshot 1)
http://prnt.sc/od9okf (Screenshot 1)
It is also sometimes possible find and place buildings which have grey borders over red unbuildable terrain. (Screenshot 2)
http://prnt.sc/od9olb (Screenshot 2)
Visible grey building borders should be reduced to former size.