Mesh Terrain and Boolean Modifiers

Hello!

Using 5.8.1

I’ve got a mesh terrain that I’m trying to cut into with Boolean modifiers. In the editor it appears to work but when I play the game, there are holes along the edges of the modifier:

Editor:

Editor show the wireframe of the Boolean modifier:

In the game:

The Boolean modifier is set to Subtract and Intersecting and the Expansion Bounds are both set to 500 in all axis.

I tried using a remesh modifier on the mesh terrain and tessellating the mesh terrain around the Boolean modifier and neither works. Any other ideas?