Scaffolding not removed

I wanted to build this building into my town, and just started building. Later as construction began, I wanted to add an extra wall inside the building, but only realized later that doing so would merge the wall into the building, and might cause problems… and so it did cause problems! Pictures and save file attached below.

The building is essentially finished:

They even added the windows:

This is what I think had caused the problem:

Steps to reproduce:

  1. Plan a building, then start building.
  2. Add a standalone wall into the building that is already being built without stopping the construction.
  3. Watch as hearthlings finish building the original building without building the extra wall and also leaving the scaffolding on.

Expected Results:
Scaffolding being removed.

Actual Results:
Hearthlings leave scaffolding.

The attached save file is quite “big” as in there being 41 hearthlings, and things could be quite laggy.

(dropbox, 'cause it’s huge)

Version Number and Mods in use:
build 2881, no mods

System Information:
Windows 10
Intel i5-3450
AMD Radeon HD 5700

EDIT: side note: there is another unfinished building in the save file that they won’t build, and I have reported it with an earlier version of this town over here, but the issue still persists.

EDIT2: Pausing the building and starting again seems to solve the issue, as they will start building the extra wall; however, there is no way to remove the added wall from the blueprint.

Bonus: After trying to remove the building, my hearthlings decided they don’t want to.

Save file: