Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Question on Adding Water to Levels

Looks like the "issue" visually is because of the terrain beneath it being rugged, making the refractions (reflections through the water) seem jagged and edgy.

Use the terrain smoothing tool on the terrain edges and the sea-floor