DepthStencilState.Default;
I did find a point in the code where it was possible that the blendstate may have been changed to alphablend, which would have been a problem but shouldn’t have caused the display in the first video.
If you look at the water in the first video, you can see that the water is interfering with itself.
Since all of these pixels have an alpha of 0, there shouldn’t have been any alpha blending. The nearest pixel should have ended up in the depth buffer.