Mob X-Ray Water Glitch, 1.16 Snapshot

A simple X-Ray glitch that can be used to detect mobs/entities through any terrain or visual blocking.

By setting up a water pool similar to this one (2 blocks deep)

And hovering underwater at just the right height, with the camera slightly tilted downwards:

That pig I X-Rayed was completely sealed off:

This bug may be related to other chunk errors, but I didn't find it where I searched.