It's been a few days. I managed to contact a GM in-game and they told me that the timer had been reset recently and I have nothing to worry about, but the Timers tab still says my house will be demolished within the next 6 days.

I also made doubly sure that it wasn't a shared estate I might be mistaking it for, by talking to all of the friends I'd shared with and removing myself from theirs/them from mine. This is the only house besides my Free Company house I'm a part of, and that one doesn't have a demolition notice.