I'd try checking for any Corruption/Crimson nearby, if it is relatively close, even though it's not saying from the yellow text that it's the cause, it might be the cause.
Other than that, I'd try double checking that all the walls in the house are completely filled, it is possible for there to be a gap in the walls behind the bed or table, I'm guessing that the house already has full walls though, but those are my 2 best guesses, aside from that, I'm not completely sure what could be causing it.