I feel your pain. I ran Crota over and over again last year before the raid completion stats tracked correctly, gave up trying given how glitchy the final encounter was. Started running it again a couple of months ago, initially to see if I could solo flawless it on hard (which I did) and after seeing exactly the same loot from Crota on virtually every completion the crux dropped for me this morning. Whether or not it had anything to do with it, this attempt was the only time I've bothered to put on Glowhoo and the Crota's End emblem. I've never thought it mattered and it still might not have had anything to do with it, but these two dropped for me on every single recent Crota kill, not today though instead replaced by the crux. If you haven't done the same, give it a shot.