Looks like that bug has spread to loading households now and not only Sims dying.
For me it worked to load the lot in build mode. That apartment was then fine again but as you say, that makes the other apartment having worth 0 furniture.
I'm guessing this is related to way objects are tied to apartments since they are all tied to the 'master' lot. Seems the game doesn't know what to do and probably directly has to do with the festival fix.
This was happening in my game months BEFORE the supposed fix that was rolled out for the festivals. I stopped playing in appartments 6 months ago because this was happening when I moved neighbors into apartments after moving in the sim family I was intending to play.
