Levitation with a level of 128 or higher modify your fall speed.

To have a really slow fall speed I use this :

/effect @p minecraft:levitation 20 253 true

All work good but when I hit the ground I'm projected very high ...

Steep to reproduce :

1) Go high

2) Type this command : /effect @p minecraft:levitation 20 253 true

3) Fall and hit the ground

It's really annoying in survival gamemode : Infinite fall (so, multiple fall damage -> Cause death if the effect last too long)
I'm not against the fall damage but against the projection...

P.S : I haven't tested this on older snapshot