Near Death Kangaxx..

[M0NSTA-]

I've just come out of underdark and remembered that I hadn't killed kangaxx yet, so I've cast all my buffs and everything and attack his first form.
Well I can get it to near death, but thats it, he talks to me once he gets to near death (is this where he should transform into the demi-lich?) but then he just keeps casting spells and hobbling around. I'm doing upwards of 100 damage a round to him but he just won't die, or transform for that matter. If I stop attacking him he starts casting spells normally.
Is this a bug or am I attacking too fast and he cant transform or am I just doing something wrong?

[dj_venom]

That problem also occurs if you attack before the dialogue is completed, ie. he is still blue. If you try again it might work.

[KaaH]

if yes and your character is under pro undead, the lich can't see you, resulting in not completing his dialog, preventing going red by himself -> not changing to demi-lich - happens to me in one game