On top of this there is also a bug in the same quest chain, Medicine Masker, Tasty Wurm Segment is an item needed for Skyscale Medicine Masker achievement.
Bug: This item drops only from [Group Event] Defeat the great jungle wurm (15) event.
It should also be dropping from hunting jungle wurms. World boss and champion wurms will give significantly more meat. You can see the item drop in a chest from regular jungle worms however it doesn't progress the achievement.