Creating ocean, BUG where parts are just white

I followed a tutorial to create a large ocean but am having an issue where large sections of it are white but the rest looks perfect. Please let me know if you have any insights.

Here is the original tutorial:

which parts in the image are just white?

Sorry i dont mean just white, but lighter, see how most of the image is detailed black

can you provide a link to the file? it could be several things, weird material setup, 2 meshes in the same place, etc