When I was ordered to build a very long building acting as a fortificated wall, I just figured out that people still wants to build scaffolding and ladder nearby already completed part of a building.
I think this behavior occurs very frequently when distance between completed part and incompleted part is very far.
I looked around bug reports or some thread similar to this and I found that they were talking about fully completed building.
So, maybe this is not a bug…?, because they start to remove scaffoldings after entire building complete.
But I think this behavior is very inefficient and makes serious timeloss.