The first thing I would try would be to save the household, with house, to the library. Then bulldoze the lot. Put the house with household back down again and play. See if it still happens. If so, I'd save the household without the house to the library. Put them in a different house and see if it still happens. If not, it's something about the house.
When all else has failed for me, I've taken a copy of the family/household from the library and put them in a fresh new version of the town. You'll loose relationships but not careers.