Blacklist temporarily disabled when opening it.

Time: Sept. 26 2013 @ 10pm EST
Frequency: every time
World name: Adamantoise
Character name: Pusywillow Katnipp
NPC name: n/a
Monster name: n/a
Class/Level: n/a
Party or solo: solo
In-game time: n/a
Area and coordinates: Uldah (other main cities doesn't seem to happen)
Steps:
1. Add current spammer to blacklist then close the blacklist window
2. then re-open the blacklist window
3. during the 1-2seconds it takes for your blacklist to visually populate spam messages from people you had already blacklisted still come through.

Note: this might be because I have 80 people in my blacklist due to the amount of spammers there are. Because my list is longer it takes longer to load and therefore that's how I noticed this issue.

I had a similar occurrence with a shorter list of people, less than a dozen. I remember because I had the blacklist open and at the same time the message of a user I had banned just appeared.