Upon reloading the world, horses, donkeys, and mules no longer retain their stored jump.

In a recent update like 1.20, horses, donkeys, and mules gained the ability to remember jump commands from the rider. Thus, if you press the jump key while the horse, donkey, or mule has no footing, it will recall the command and execute the jump upon touching the ground. However, the issue arises when exiting and re-entering the world: the command to jump and its strength aren't saved. Consequently, if you command a jump midair, exit the world, and then re-enter, the horse, donkey, or mule won't jump upon hitting the ground as expected.