The latest preview made some changes on how some mobs such as Horse, Mule, and Donkey gets tempted by holding a Golden Apple/Carrot or Enchanted Apple, and Llama and Trader Llama gets tempted by holding a Hay Bale.
However these changes didn't get implemented in the game because the files are not stored in the correct folder. The JSON files are supposed to be located inside the entities folder, but instead, it is in the vanilla_1.20.10 folder.
The obvious solution is to move the JSON files to the correct folder.
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In 1.20.10.21, horses, mules & donkeys are tempted by golden carrots & golden apples (+enchanted) but also hay bales which should’t be. Llamas are not tempted by hay bales