Levitation effect resets its amplifier to 0 when quitting and reloading a world

Giving yourself a levitation effect with an amplifier will reset it to 0 when you quit and reload the world.

How to replicate:

1. Give yourself the effect:

   effect give @s minecraft:levitation 86400 255

2. Save and quit to title screen
3. Join the world again, you should now be slowly levitating upwards instead of staying at the same height