Go N of the monster's habitat to the Griffon Outpost PQ. Wandering around here should get it for you. If it doesn't, then near The Blighted Farm PQ (on a cliff above the Griffon Camp) I fell off the SE face of the cliff, into the camp. While falling I got the unlock. Can also be unlocked at 57.1k, 35.3k by walking into the entry of the Griffon Outpost PQ.
