version: Apotheosis-1.20.1-7.4.4

When using a sword with the loot pinata affix to kill a donkey carrying a chest, the loot pinata proc'ing will affect the chest along with the contents of the chest. This allows duplicating any item.

Are you able to reproduce this duplication exploit using llamas instead of donkeys?

Yes, the exploit works with llamas, trader llamas and mules too. I can't reproduce it with any other (vanilla) mob.