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.

Having the "Glowhoo" shader on you is actually a pre-requisite of acquiring the crux, i do believe that you can have it just in your inventory, but i had it equipped when i got the crux so good luck with that

Hey Dave, Make sure to acquire and fully upgradethe Husk of the Pit, and subsequently Eidolon's Ally, before pursuing the Crux of Crota.

Another week and it's still broken...

Sorry, It is a rare drop. There is nothing to fix. It is all RNG, so it is random. Good luck!