Waterlogged blocks have a glitched texture.

Bedrock has this weird glitch with the texture where random waterlogged blocks will have a faded mossy stone brick texture applied to the top of them. The glitch appears every -4 blocks starting from from 0, 0, -1. It looks like it only shows up in 2x2 waterlogged areas though. There's also a glitch with seagrass where the seagrass texture is applied making the water completely invisible. That glitch occurs naturally so I have no idea how to replicate it.