Same here. Last version, either SP or MP.
Once a building is built, cannot place new or replace furnitures.
Hotfix not enough 
R841.
I built a building that had a bed.
When it was finished, I undeployed the bed.
I opened the placement menu (“Place an Item” - the one with the hotkey “P”) and was able to place a chair (that I had already crafted) where the bed was before.
Could you please share your savefiles? Maybe this is broken for the savefiles from r840, or something else is broken, since the Thursday build and the hotfix build seem to have introduced many regressions.