BUG - Sims 2 Legacy - Unable to go down stairs

Just encountered this one, my current family live in an apartment building in Belladonna Cove on the top floor, and they are currently unable to go down stairs. A cat and a delivery boy have since come to the floor, and neither of them can descend either, even when I distract one of them, as I thought the issue was multiple sims/pets trying to access the stairs at once. Even when it's just one character though, they still can't descend. I'm attaching my logs in a zip file because in the ctrl+shift+c menu, I could see there were definitely things going on, but it's beyond my capabilities to fix them.

Let me know if you've come across this too!