You claimed you have actually blocked that IP address, so it makes sense that it will be matched as a blocked IP address.
I tested this:
I see the hostname and a "Block IP Address" button
2. Clicked in the button (what you did)
3. The page refreshes and now, as the IP has been blocked in step 2, a new message states:
Matches blocked IP addresses: 18.104.22.168
As far as I can tell that is working as expected. If you want to double check and see whether that IP address is actually blocked in the database, you can run the following SQL query, if you know how to do it:
SELECT * FROM qa_options
WHERE title = 'block_ips_write'
Anyway, it should be there, as you have blocked it :)