Summoning items not dropping from Torment bosses

I’m trying to gather materials for the Duriel boss fight in Torment, but the items aren’t dropping from the requisite bosses. I defeated Grigoire on Torment (twice), but he didn’t drop a Shard of Agony. I also defeated Echo of Varshan on Torment, but he didn’t drop the Mucas-Slick egg(s).

To eliminate some inevitable user error questions:

  1. Yes, I am sure I am set to Tier 4

  2. Yes I checked my consumables inventory. This vid shows the end of a second run at Grigoire that shows both the drops and my inventory view. No Shard.

  3. Yes, I completed the quest(s) alone and was therefore the one to summon the bosses. (See above)

Reporting this as a bug bc I don’t know what else to do, but any suggestions welcome!