The issue is that newly blacklisted domain carries forward the "hits" number to top advertisers. Ideally it should be reset to zero and counted anew.
I just blocked a domain with 3000 plus lookups and that 3000+ number moved over to Top Advertisers list. But 3000 hits wereen't really blocked.
This will be addressed by our upcoming FTL backend. A domain with a huge amount of queries (let's say 3000 queries, then blacklisted and again 3000 queries) can then even appear in both Top Lists.
The technical reason for this is that to speed up the process of generating stats, a query is said to be blocked if it's domain is blocked at the current time instead of going through the log and checking if it was actually blocked. The latter method can be inaccurate and takes a lot of time, so in order to speed things up (even though it can still be slow), we use the current method.