Description:

When a player reaches a certain y co-ordinate (for me it was 10,0291) the player becomes frozen in place and cannot move by any means. If the player tries to save and quit the world, Minecraft will be stuck on the saving world screen and the only way around this is to force quit Minecraft by closing the Minecraft tab, using Task Manager, etc. This affects creative mode in both fly mode and normal mode. However, the bug causes a lot of lag in survival. In survival, you will either take damage but won't fly away rapidly or die and be stuck on the "generating world" screen when the "respawn" button is pressed. If the player doesn't die, it will just be really laggy and the entities won't despawn for some time.

Expected Behavior:

The player should continuously be accelerated based on their velocity, which should slow down over time.

Current Behavior:

The player gets frozen and is unable to move if they get accelerated to a certain Y level and are in creative mode.

Steps To Reproduce:

1. Get into creative mode.
2. Stack explosives on top of each other until there are enough explosives to launch you to Y level 10,0291. I used a command block and end crystals for this.
3. Ignite/ activate the explosives to get launched.
4. Wait until your Y level stops increasing and does not decrease. You will be unable to move.

Video Showcasing Bug:

https://youtu.be/h9wd7tJlbQ0