Trouble spawning Filth Fiends (Bust the Dust Kit)

Haven't been cleaning your sims home have you? They spawn for me long as I don't have my sims interact with them and their relationship is low. Could try shift clicking on them and see if the option pulls up?

Hi LadyKyn!

Thank you so much for your reply.
I have indeed let dust and dirt pile up, I even managed to get the house to "filthy" status, but no luck.
I even tried moving the dust bunnies to a locked room and confirmed that when the little tune plays that I assume marks their conversion into filth fiends, they just disappear.
Shift-clicking doesn't give the option to make them into filth fiends unfortunately; it just says reset and set as head, I believe.
I even tried in another household, small house with a slob sim, and this time not even the dust bunnies appeared! I really don't understand what's wrong with my game at this point. I triple-checked that the dust option is active, they get the "this house is lived in/dusty" moodlets.
I tried taking out all mods and repairing the game as well. I'm very confused, it must be a bug. I should probably try in a fresh save.

Thanks again!

EDITED June 25th:

I managed to get one to spawn! Seems like the house I was playing in had a secret basement room and they might have been appearing there without me noticing, not sure. I just let time pass and was finally able to interact with the filth fiend. It just took a lot of time, and it wouldn't appear until the house was "filthy". All dust bunnies just disappeared at that point, too.

Thanks again!