I got a Faded Salil's Writ to drop from one of the goblins at Lord Bergurgle's Spawn point. Looking at the level of the Corrupted Shaman (level 40), that seems like the right level range for it to drop. on 7/24/20 in Lake Rathetear. I am guessing that it was the Corrupted Shaman that dropped it but not 100% sure it was....I just know I got a Faded Salil's Writ to drop while helping a cleric for Lord Bergurgle and killing the other goblins , tainted and corrupted as well.
-Galdill