(Bug) - Tested on Single Player and on a Server
While mounted, both the player and the horse take fall damage over modest hills and cliffs, like players are already used to unmounted. Player takes x amount of damage, Horse takes x amount of damage. As one would expect. However, if the player dies while mounted, the damage that the horse should also take doesn’t apply.
Meaning, if the horse is at 75% health, and the player is at 1% health, and you jump off a modest cliff, the player as expected will die. But when you return to the horse, the Horse retains its 75% health (I used admin warp to instantly go back to the horse on death, so it wasn’t healed in the time between my death and getting back to the horse).
The same can be reproduced when both the horse and the player are at 100% health. If you jump off a huge cliff that results in an instant death, the horse will have 100% health while the player will die.