The bug:

If you summon a piglin with the /summon command, it will not be attracted to gold items and will not pick up those gold items.

How to produce:

1. Using the "/summon piglin" command in The Nether.
2. Throw a gold ingot (or any gold item) at this piglin.
3. Wait.
4. You will notice that the piglin did not pick up the gold ingot, nor did it react to this ingot in any way (such as being attracted to it), even though the game rule mobGriefing has been set to true.