The bug

Vertical lines of a pixel thick appears on the sky when the player is stationary while looking at an axis. The lines instantly disappears when the player moved. Few example when the lines appear: After loading a new world, player starts sleeping, after sleeping completed or respawn.

How to reproduce:

1. Load a new world
2. Set field of vision (FOV) to 90
3. Look at the sky

OR

1. Right click on bed when it's possible to sleep
2. While sleeping, look at the sky
3. After sleeping is complete, set field of vision (FOV) to 90 and look at the sky