Zul Gurub bug with bosses. Unable to finish the raid.

[painmachine696 0]

My guild was running Zul Gurub and we went to kill Venoxis, the snake boss and he was seemingly missing/invisible. We chocked it up to a random error and assumed he simply despawned or something then cleared the entire instance per usual. However, when we pulled Hakkar he was doing the poison debuff that venoxis gives him so we wiped and had to call the raid since we obviously couldn't go back and kill the snake boss. I know its only a 3 day reset but we'd all like to get our hakkar kill in. Our raid ID is 18704