I looked again today and noticed they are selling Swarm Mother's again. They sold it Jan 26th, Jan 5th (as giant spider), and Nov 17th.
Do the devs just pull items out of a jar? Darts on a piece of paper? There doesn't seem to be any kind of meaningful rotation.
Just trying to get a helm from a dungeon that I have not been able to successfully PUG yet (Ruins of Mazztun). Seems harder to pug this dungeon than some of the even later DLCs.
According to
http://benevolentbowd.ca/games/esotu/esotu-chronicle-of-alliance-point-vendor-items/
The helm was last on sale in September of 2016.
Yeah, I know the helm isn't that great, its just an eye poking gap in my collection.
Course it took me months before I finally got a PUG that could do the mechanics in ICP or COS. Seems to be as much RNG in this as the items themselves.