Overview

This is a bug that occurs when you move in a vehicle at high speed.
Strictly speaking, the game does not freeze, and it becomes impossible to read chunks. You can enter commands.
This bug has occurred since 1.14 and not in versions before 1.13.2.
In addition to the same conditions as this task (= duplicate tasks), there is MC-176240 as well, but no one noticed the slurring noticed in the OPEN state, so we made it.

How to reproduce this bug

First, in order to create a one-sided blue ice world, please enter and generate the following preset in Super Flat. (Please create a village if you do it in survival mode.)

minecraft:bedrock,59*minecraft:stone,3*minecraft:dirt,minecraft:blue_ice;minecraft:plains

Once generated, place the boat and continue rowing in any direction.
Then suddenly the chunk read starts to slow down and eventually the read stops altogether. (See attached image file)

It becomes more noticeable on low-end PCs, and if you log out in this state, the title screen cannot be displayed and freezes. In this state, the close button also doesn't work, so you can only forcefully close it using the task manager.
You can escape by using the teleport command etc., but in survival mode where the command cannot be used, you are forced to close forcefully.

Please see the attached file or the link below for a video that practices the above.
 
https://youtu.be/4rFqBblPQDk

approach

No workaround has been found other than slowing down.

For this reason, it is a serious bug that needs to be fixed immediately.

**Added on October 10, 2020. : A serious bug that hasn't been fixed yet. Is Mojang not good at fast vehicles?]

**Added on March 6, 2021. : As of 21w08b, the speed of freezing with the same specifications has been reduced from 252km/h to 700km/h. However, it is not yet complete compared to 1.13.2 and the bug has not been fixed. I would like to expect future updates.