Summary:
From my searching, this is a previously discovered issue… but it’s been around for over a year, as seen here:
The reason I bring it back up is because 1) That bug report was marked as “Resolved”. 2) It wasn’t fixed.
I have been dealing with the same issue today, where Hearthlings will refuse to place easily reachable items within a building (specifically ones that were placed as part of a schematic). I thought it might be my specific building design, but when I used my schematic again, it was inconsistent whether or not they’d complete it. As one person mentioned in the thread I linked, saving and reloading fixed the issue, but obviously that isn’t an actual fix. I’m guessing the game isn’t correctly checking for incomplete tasks, and finds the incomplete tasks when you reload the save.
Steps to reproduce:
Tell your hearthlings to construct a building.
Here’s the save file. This is the one that when I reloaded it, they started placing the items. The houses that they weren’t placing items in are the three red roofed houses, which are all identical. All the items were placed with the “Design Building” menu before clicking “Build!”
One other thing that is confusing. You know how when you have either the “Designate Zones” or “Build & Design” menus open how all the planned items/buildings show up as semi-transparent? Some items are actually showing up as semi-transparent without any menus open, such as the tables and benches in two of the red-roofed houses, but not in the third one. I know if you use the “Place Item” menu, items you put down will always show up as semi-transparent until placed, but this isn’t the case with items as part of a building.