Massive lag spike near water.

During Legion league, everything was fine. but came back near the end of Blight and standing close to water (Brine king) my game goes down to 1-5 fps, cause heavy load on my PC and I never changed any graphic setting.

The game become unplayable near water. and even use scaling resolution, it drop all the way from 2K to potatoes and game still run at 1-5 fps with graphical glitch.

i had this problem too few months ago, only thing that helps is setting water detail into "low"