It functions like many other quests where you need drops, the more people needing them (have the quest), and the less that have been looted, the more they drop. So it's always best to keep them in the advanced loot window until enough drop for everyone. Conversely, the more people that have them in an inventory (or several people), and the few people who have the quest, the less common they are to the point you won't see one.
Alternatively, one person can hand them and get the quest anew in order to up the drop rate, if it allows you.
Edited, Jan 31st 2023 9:58pm by hotrod
Edited, Jan 31st 2023 9:58pm by hotrod