Plane Reflection only works in Editor

Plane Reflection script and shader from The Blacksmith imported in a working project. Seems like I've made everything like the demo, but reflection only works in the scene window. Everytime I start scene, plane acts like ordinary Standard Shader. As I open scene window, it starts reflecting. And after I switch back to Game, it freezes the reflection right where it were in editor. Changing camera position doesn't make anything on perspective of reflection.

Anyone experienced it?