The drones are trying to build roads inside my village. They do the "walking to worksite to build road" action with the path leading to a location next to a road that I built within the range of my village (image 1). This has led to massive numbers of drones (image 2) trying to enter my village to build roads, which is very annoying. They appear to focus on the two diagonal paths near the edge of my village (middle left and lower middle of walls in image 3). They are also trying to build roads from the corruption that connect to my village roads (upper left and lower middle of walls in image 3).
I'm in the region Wilderock. This issue didn't start until I had built most of my walls, but I don't know if that's what caused the issue.
I'm playing Release 1b on Windows 10.
I managed to ameliorate this issue by connecting my diagonal roads (so that the sides of the squares are connected rather than just a sequence of corners). I found that drones seem to want to build roads in the gaps in the roads in my town: if I remove a square of road in the middle of a straight road, the drones will try and build a road there. So, by removing the "gaps" created by my diagonal roads, I made fewer places where the drones wanted to build. I also found that the drones will try to build on roads that are assigned for upgrade, usually when a villager has already placed the upgrade material on that tile.