When I order my hearthlings to build a road, they no longer remove all of the dirt first. They remove most but leave at least a few.
Steps to reproduce:
1) Build a road. At least 20 blocks in size should produce at least 1 bugged area.
Bug free road.
Blocks flash between dirt/grass and road.
Probably happens with floors as well. I believe it is due to the new multi block building from alpha 19.
Version Number and Mods in use:
Alpha 19 Release 687