[BUG?] Hildana Deathstealer

I just killed Hildana Deathstealer (rare spawn in Icecrown) right outside the Valhallas ring. About two minutes later, I flew down to the southern part of Jotunheim and found her again and killed her. I immediately did a thorough check of her spawn paths and did not see her.

Do rares normally have the potential to respawn almost immediately, or was this a bug?