If your guild killed Setri Lureth prior to the patch today (Tuesday March 28th) your guild was not awarded the in game achievement. Those kills can be submitted manually without future kills overriding the date. The necessary adjustments have been made to that kill in the ranks so it does not.

Also, flawless achievements have been added in to census as well with the patch today. These were obviously missing entirely when the zones first launched just a few weeks ago. These will be added to the ranks shortly, but they will probably not get added in right away. Flawless achievements are obviously not scored as ranked progression but only used as bragging rights. I don't think guilds will feel a huge need to submit these kills manually using dates from personal achievements but if guilds so choose then so be it. Otherwise, flawless achievements will just begin starting today for those expert raids (So don't die!).

Good luck Raiders!