I just got a message that I failed The Sealed Missive, at the end of a fight with an Adgragan and some Water Blights near the east end of the Adra Pillars. My party was to the west of the Adragan, and north of the Adra Pillars. I was exploring from west to east and had not even discovered the northern bridge. I found the Dying Monk's loot on the east side of the bridge.