It was the White Guardian that poisoned me this time, actually. I seemed to be fine, spell exhaustion was working as normal (I healed myself several times during the fight) but after the Guardian died I noticed my poison wasn't fading away. I thought it must just be a really long duration, so I headed towards the assassins, healing myself along the way. When I got to the assassins I got blasted several times, so I hit recall, then I got stunned. Recall faded away and I was placed in the clan area, but the stun, spell exhaustion, and poison all remained for well over a minute until I died and hadn't faded at all.