Second story floor queued before first story walls

Support Bug Reports
#1

My hearthlings are trying to build the second story floor before the walls of the first story.

20180723185418_1
20180723185418_1.jpg1920×1081 198 KB

Save file: https://drive.google.com/open?id=1NwfLP5xtpgLzGglvfo8De2zc9r1q7NfL

#2

Did you use the slab tool on the second floor?

#3

Nope, used the room tool. Only time i used slabs was on a few parts of the roof.