If the generic.jump_strength of a player or an entity is set to a value high enough, to make them jump above their generic.safe_fall_distance, they are capable of taking fall damage on, or if the generic.jump_strength is set high enough, even above the y-level, they took off at.

Expected behaviour:

Players and entities can't take fall damage above the y-level they took off at.

Steps to replicate:

1. Create a new world, set "Allow Commands" to "ON".
2. Open the chat.
3. Type / paste the following command: "/attribute @s minecraft:generic.jump_strength base set 1"
4. Press your jump key and wait until you reach the ground.
5. You just took fall damage.