How can I solve problems with Remesh modifier? I used the Remesh modifier to turn an Ocean modifier blocky and this happened. What's going on?

The model shown below should just look like normal terrain, but it doesn't. There are walls covering it.

View from inside:


View from outside:
I guess it's not bug, as the Remesh Modifier page on Blender 2.79 Manual explain this problem and how to solve it :


Just add a Solidify Modifier, set the Thickness to 0.5, and make sure the Solidify Modifier is processed before the Remesh Modifier but after the Ocean Modifier. The order of the modifiers should be, from top to bottom : Ocean / Solidify / Remesh.