Custom Lots load as empty with only a mailbox

Hello!

I am having a strange issue with my game. I've followed all the instructions perfectly and have everything updated. However, I cannot load custom lots at all. I can place it, and it appears in World, and I can build/edit, but when I move in a household, all that loads is the Sim standing in front an empty lot with the mailbox moved to the back.

If I am playing a base household, my placed lot does not appear in the neighbourhood view and a Sim cannot visit it. The action just disappears.

I've been looking for a solution all night! Does anyone have any idea what is going on? Broken CC possibly? I filtered out broken ones that caused crashes when adding a vampire already.

Thank you in advance!

UPDATE: The problem is worse than I thought. My Sims can't do ANY actions and any time I try to save, it fails. They all just disappear immediately. What can I do?