I've had the same problem with no mods installed.
Not entirely sure if or how this is reproducible - that said I do believe it may have something to do with the new house upgrades you can get once you've maxed out your house level. On my first day trying out the new update I wanted to check the price of the new room additions but when I clicked on them at Robin's the room just appeared for free. I don't have the need or space for extra room in my house right now so I got rid of it right away ... and a few days later (in-game) this happened.