So, a secret near the beginning of The Whisper did the following for players A, B, and C in my fireteam, the same fireteam of players A, B, and C were present in every run:
Run 1:
Player A shot the secret object, received White Nail II, III, and IV
Run 2:
Player B shot the secret object, received White Nail II and III
Run 3:
Player C shot the secret object, received White Nail II
Pretty sure a for loop that rewards all players was messed up somewhere, and one player receives as many upgrades as members of the fireteam don't have the next upgrade. ¯\_(ツ)_/¯