This one is tricky to explain, but easy to reproduce.

1. Spawn a piglin OR use /summon to spawn a mob with CanPickUpLoot to 1b.
2. Throw two pairs of diamond leggings near the piglin(make sure he doesn't already have golden ones)(you can use any type of armor except gold).
3. Listen.

Affects:
-Piglins
-Skeletons
-Wither Skeletons
-Strays
-Zombies
-Husks
-Drowned
-Zombified Piglins
Only seems to work with diamond armor