It happens every once in a while to my chars on 2d and how you solve it is to go into menu on paperdoll, Options, Miscellaneous (look for the UO symbol). There is an option to cache this many houses, and all you need to do is slide that to 0 or 1 then log out. What is happening, is that your client is picking up a building that was cached. It happens alot if you xfer a char.