Trophy Mob Khrin bugged / disappeared

The trophy mob Khrin ( http://daoc-trophy-mobs.com/mob/khrin.html ) in Delling Crater disappeared when I got close to it and stays absent for hours on end until presumably the next server restart.
After days of trying I have only been able to kill him 2 times so far. It also does not respawn within the usual timeframe (or maybe it does underground).
Please take a look

Thanks