See attached image: GroundClay - Viewport and GroundClay - Render for the difference.
Also attached is the original Blend file packed with the images and node setup.
Made on macOS Blender 2.79b with RPR 1.6.159.
Expected result: the Production Render should be as "displaced" as the Viewport render is. The difference is very apparent from the screenshots.
Rendering was done on 1x eGPU only.
MacBook Pro 2017.