Bug with newes patch 1.41.38.1220.

Today EA released a new patch prior to the cats and dogs stuff pack, supposedly fixing some in game bugs. Well, now those that have patched have a bigger problem according to Crintic... Apartments, Houses and rooms furniture disappears. So, if you decide you will patch your game, which usually is not the case with us that play the G4TW Sims 4 games, back-up your Sims 4 floder in My documents location to a new one with a new name. In this way you would have a back up of your builds and saves and all mods and tray items. Be aware that at the time of this post no fix had been found. I would advice to refrain from patching until the problem is solved. I hope this helps. One of those times I'm glad I wait to patch, until G4TW uploads a new fix.

Look to me like a mod-related problem as I have no problems with this update (no mods in my game)
Move (temporarily) your folder mods from Documents\Electronic Arts\The Sims 4 to f.e. your desktop and see if the problems still persist

I read this mostly affects apartments 'only', so one could try avoiding to play in apartments altogether - at least until EA fixes this with a new patch.

It figures, now that I actually enjoy playing in an apartment the game bugs out.