Hello,

The further away you get from the coordinates (0,0) in your world, the more the player's camera lags. I've attached some videos showing how the camera behaves at distances of 100,000, 300,000, and 500,000 blocks away. No worries about the video quality. I had to lower it to be able to submit them here. It's also noticeable that the third-person camera is the first to start experiencing this bug.

You can reproduce the bug in your world by following these steps: Create a world with cheats enabled and teleport yourself approximately 500,000 blocks in one direction. You'll notice that walking starts to feel choppy. It's like constantly hitting an invisible wall that moves a pixel forward each time you touch it, causing you to hit it again and again. If you switch to third-person perspective and look down at your character (as shown in the video), you'll see that the camera doesn't move smoothly anymore but rather jitters to get to the 'right' position. 

This bug gets worse the farther you move away from the center of the world. Eventually, you may even find yourself unable to move at all.

Because of major updates that regularly come into the game, you're forced to travel long distances, whether to discover a new biome or simply explore the world for structures with good loot.
Mojang, this is driving me to despair. I'm dead serious about this. Either way, there's a lot of traveling involved. As players, we're given this unbelievably vast game world, but we can only use about 1% of it. This spoils the fun for me, my friends, and surely for other players too. Plus, it's incredibly depressing to always remember that most of your survival world will remain hidden.

Mojang, this is driving me to despair. I'm dead serious about this.

Edit:

Now that I've published the post, I realize that the bugs in the videos I created are hardly visible due to the necessary low video quality. That's why I recommend taking another look at the bugs in your own world.