On Agnarr we've killed two Ancient Jarsaths so far and neither have dropped their VP key piece. Not sure if this change is intentional or not, would love to see some input.
Unable to verify. an_ancient_jarsath has a 100% chance to drop 19960: Piece of a Medallion, with no restrictions. NPC always had the item when I spawned and checked him on Agnarr.
I'm sure he will start dropping loot on Agnarr as soon as the server officially unlocks Kunark in 5 minutes!