https://shalazam.info/quests/185-map-fragments
You need to complete Scavenger's Path in order for the fragments to drop it seems, based on comments there.
Can confirm it still drops from the Supply crates in goblin cave, got it tonight, after about 6 days of camping the goblin caves for about 2 hours a day.
These appear inside of the little waterfall cave, south of the binding point on lower bridge. There is an invisible wall preventing you from entering the cave. I assume this is a part of the quest "On A Hunch, Pt. 2" but I could be mistaken. Either way, you cannot get in this place without abusing DL's teleport.
I did which then allowed me to pick up the Nalis quest "A Deeper Investigation" were you have to walk over fire pits in the camps.
Turning that in put me on his "Interception" quest listed above. So Gonadoit's post above is actually Pt 2 and Pt 3.
I just need a solid answer. When/how/where does he spawn. I've camped at the listed location on the map and combed through reddit/discord/etc. and CANNOT find anyone that gives a straight answer as to how/where he spawns. Grats to everyone on their drops.