Summary:
Throwing/shooting a projectile while having a downwards/stationary levitation effect makes the projectile shoot straight up at high speeds.

Steps to Reproduce:
1. /effect @s give levitation 1000000 (value)
2. get a bow and arrow, splash potion, or similar
3. use the bow/potion/similar
4. Make sure you are looking up to observe the entity flying away from you.

Observed Results:
When shooting a projectile with the downwards/stationary levitation effects, the projectile shoots completely straight up.

Expected Results:
The projectile should be moving in the direction that the player is looking.

Notes:
MC-10755 does not duplicate this issue; the levitation effect itself works as intended despite being at high levels: the player moves downwards or hovers in the middle of the air.  Instead, what is being reported is the projectiles use during the intended effect.