Again you concentrate only on the update part, explain this then:-Because the filters are read locally from your machine. When you do an update you have to download a new file which replaces the old filter list.
he added only 2 new filter rules.
The site in question has in total 6 or 7 rules. Thus atleast 4-5 rules were pre-existent.
Even if I had that filter rule problem as you say, the locally cached filters in my machine should have shown the rest of the 4 or 5 filters relating to that site.
But it didn't.