Sorry for the late reply! I haven't had time to play much since but I remember it being when I activated the on-map stash.
Thanks for the tip on Advanced Knowledge. I don't think I've made it that far in those locations yet so I suppose that's on my list! I know my character is probably strong enough, I just usually have a full inventory well before then haha. I know when I was looking for info on it the first places I looked were the computer and the Esc menu help/knowledge screens if that helps.