Sims keep freezing

After the base game update and the Enchanted by Nature pack and nature's calling event started, my sims have been freezing up. I don't have any cc or mods installed. 

Suddenly, and without a correlation in what they were doing, one sim in my family freezes up and doesn't do any of the tasks, I queued. The problem is, when one sim freezes one by one the rest of the family starts freezing too and I have to reset them until I find the one who initially froze up. If I reset one that wasn't the first to freeze it doesn't work, I have to reset patient zero - so to speak.

I have noticed going on walks with my dogs does set it up more often than other tasks. The family I've been playing with is living in the horse ranch world on the biggest lot and includes a ghost, 2 other sims and 2 dogs, in case that makes a difference.