The glitch in question removes water shading and fog. This glitch occurs when the player's head gets inside of some partial block's hitboxes but not all. This glitch usually occurs when the partial block is beneath a non-water block, such as air or coral blocks (for example).

This glitch can be replicated by placing the following blocks in very shallow water:

-all coral fans

-all types of pressure plates

-all types of trapdoors

-daylight sensors

This glitch specifically does not work for some blocks:

-most plant blocks, such as dead bushes and kelp.

-cobwebs

-doors

Coral plants can also activate this glitch, but need to be beneath coral blocks for the glitch to work.