So the other day I was playing on a longer server of mine in Hamlet. I started the Aporkalypse, killed the Harold and happened to die on my way back through the ruins to go turn it off. I respawned in my house via Meaty Effigy and... there were Ancient Spirits in it?
At the time, my house consisted of four rooms. During this period I only saw three of the rooms before I left (I mean, I wanted to leave and... not die) and two of them spawned spirits, but oddly not the third? I killed all the spirits in my main room (the one the outside door enters into) and entered the room with no spirits, did some stuff, then went back into the main room and they had respawned as they do in the ancient pig ruins if you leave a room. I'm guessing it's reading my multi-room house as a pig ruin or something similar? Lol. Really gave me a shock and nearly got me killed on a reasonably old server, which would have been a bummer.
I've never had this happen before during the Aporkalypse, but honestly I think I may have only had single room houses any time I happen to have been in a house during the Aporkalypse on my own servers. I observed my partner playing their own server about a week or so ago as well, and dying specifically in the ruins during the Aporkalypse. There were definitely no spirits when they respawned in THEIR (admittedly one room) house via Meaty Effigy.
I haven't attempted to reproduce this glitch a second time.