Applying bumpTextures 1 through 3 to a TerrainMaterial did not result in the material having bumps.
I have created a Playground which showcases the error, with a StandardMaterial on one sphere and a TerrainMaterial on the other spheres. The bumpTextures on the StandardMaterial work fine and produce the desired result, but not so on the TerrainMaterial.
https://www.babylonjs-playground.com/#20OAV9#757
Terrain - Babylon.js Documentation the documentation does state that bumpTextures should be supported on TerrainMaterial.
