I can't remember when this started happening but it was in the .13 betas too.

Where there is seagrass in 1 block high water there are a few places where the texture of the water is replaced with the seagrass texture. It only seems to happen where the water meets land (or in this case leaves, but it happens next to land too).

if I remove the seagrass the water is normal, but as soon as I place seagrass again it reverts to the glitchy texture.