URL Filtering Problems

Hello Everyone,
I have set up the web proxy for non-transparent and set up URL Filtering with a wpad configured with both dhcp and https. I downloaded a blacklist from shallah as it was recommended on the wiki. I have a problem of it not blocking certain popular porn websites, however I can see it blocking other websites in the logs in other categories.
Any Suggestions?

URL-filtering in https-traffic?
How did you do that?
Or did I get this wrong?