Phasing in Icecrown bugged?

Hey, so I've been trying to complete the first few quests in the Argent Vanguard to make my way to the Ebon Hold rep quests / quartermaster but there seems to be a huge phasing issue. Currently on the quest The Last Line of Defense; in which you need to use the cannons to clear mobs outside of the quest hub, however, whilst im inside the quest hub the towers aren't spawning the cannons. So I fly out to where the mobs are and then the cannons spawn, sometimes I make it back to the quest hub to mount onto the cannons although when I do, the mobs that I'm supposed to kill phase out as if the quest has been completed and there are merely corpses on the terrain outside the hub. I had similar issues with the quests previous to this but after spending many times phasing in and out of the quest hub I managed to get them done. I also had issues with actually spawning the quest givers in general having to fly in and out of town to phase correctly.

Now after giving up I attempted to fly to the flight master and even he has despawned as if all the npc's in the hub aren't correctly phased. Is this a known issue? Seems pretty major to me; I had a short search around the forums but didn't find much. Sorry if this is a repost of a known issue and a link to a solution would be appreciated :D. Thanks

That actually sounds better than what it was a few month ago (causing your character to get stuck and random deaths). That quest always causes phase issues. You can try relogging and if all else fails, kill them the old fashion way.

Yes, Icecrown (and Storm Peaks too, I think?) has problems with on-the-spot phasing. I had to fly back out and in to fix Argent Vanguard and Mathias Lehner.

And I have to kill the 100 spiders and 3 wyrms all by myself while dps-racing with the allied NPC

Yea it's been a problem that devs are supposedly aware of...had a ticket open for 5 hours about it...even saw 2 GMs online but nothing got done...just gonna have to kill them the old fashioned way