Collections 1, 2, and 3 for the new legendaries, Hope, Astralia, and Nevermore, are listed in the same tabs as collections 1, 2, and 3 for the old generation of legendaries (only Hope, Astralia, and Nevermore have collection 4 available). Unfortunately, because collections 1-3 are all grouped together, I mistakenly thought that this meant that all of the old generation legendaries would receive a fourth collection (and eventually an associated HoT legendary) at some point in time. So, I crafted the 3rd tier precursor weapon for frostfang, thinking its fourth collection would be released at some point in time. Sadly, I just found out that this isn’t really the case, and that I essentially wasted all of my money (and time) crafting it. I would have never made this mistake if everything hadn’t been grouped together the way it is.