There has also been mention of the patch borking the spiral staircase ...
I'm having problems with
one spiral staircase on a lot. Sims will run up and down all other spiral staircases in the house, and they'll happily go up this particular one, but will not route downstairs unless I remove said offending staircase. There is another staircase they could use, but they ignore it as long as the borked one is closer. I even tried installing an elevator to give them an alternative, but they won't use it even when directly instructed to.
This is just from the patch, I haven't braved the EP yet.