Question Shadergraph position node doesn't work when no main camera rendering to screen

I have a shader graph that uses the position node (world space of rendered fragment). I use the position node to determine how I should set the alpha of an object.

The shader stops working when I set the main camera's target to a render texture. Is this expected behavior? Additionally, if I render the fragment's world space as the color, it shows all black.

What's worse, is that the behavior is inconsistent, the shader does not work on android/ios, but does work within the editor. Though, rendering the world space as the color shows all black in either case.