I haven't played in about 3 weeks, and I just returned to my simming today after patching up 1.50. Assuming that this glitch has something to do with that, because my game has run perfectly apart from that (and the rain/building glitch, but I digress...)
6 out of my 8 family members are fine, their queues were cancelled, but that's replaceable. The dad Sim however is stuck -- as is the baby he was trying to become best friends with. I saved an extra copy to play around with, and tried resetting each individual (ie. the baby and the dad), as well as resetSim *. This leads to the dad returning to normal, but no one is able to interact with the baby any longer - whatever snuggle/play I queue up hangs out for about a sim hour and then cancels out of the action queue. (And the facedown lump of baby is giving me the creeps!!)
I really hope someone has a solution to this - if not, I may ask about some rather unorthodox methods of trying to fix it. Thanks for your help!
Edit: I've cleared caches, restarted the computer and the game. I also don't have a previous save(s) of this game (my computer's a little short on storage space) so I really hope this is fixable!