Rare drops from rare mobs are one of my least favourite world mechanics but the devs seem to love them so I guess I just have to decide where they fit on my todo list.
My Shadowlands meta achievement is down to just three Maw rares that require multiple people to summon (well 2 of them, I’m a bit fuzzy about exactly how the third works) I seem to still be stubbornly committed to not doing these unless a collision of players happens naturally in the world so it may be a while, if ever, that I complete it.