Another AI bug

Alright i was out soloing sunreach from Durheim Archives. I was waiting for his advance guard to move back so that i would be able to rush him and kill him. (this would usually happen and does)

As usual about 5 wardens jumped outa the lake , but they were out of my aggro bubble and werent attacking me. However one of the wardens managed to pop out of the water right smack in front of me, with the whole entire water effect. Instanyl i had about 10 wardens trying to kill me.

I died.

I tried this 5 more times and 4/5 times this happened. Any idea how this happened or just some random glitch i stumbled upon?

They are all part of a single group and if you agro one you agro them all.

yeah thats not the glitch how did one "jump out of the water" but actually jump out of the ground...