I have noticed that the collections for "8 Legged Bits" is both a mob drop as well as a ground spawn collectible. On the other hand, I haven't gotten a single collectible for "Unfit for Adventures" and "Trash from the Past." My guess is one of those is probably from not hunting in the right area, but I suspect the other is supposed to be a ground spawn.
We are getting "8 Legged Bits" as dropped and ground spawn also. The only ground spawn set I have found is "8 legged bits". In the other zones there are 2 ground spawn sets.
I think Chilly Critters, Restlessly Shader from EW, Bare Nessessities from GD and I'm guessing 1 set from Velks are meant to drop from their respective missions. From what I read they are dropping differently that sets in the past, only from the event mobs, not as 4 points of light ground spawns or from zone trash.
Yeah, Icebound Avatar of War from the mission. We have had only him drop a collection piece to that so far. Twice.