[Warner306]

I don't have any idea what that could be. Try toggling fullscreen exclusive mode? Seems impossible to get different colors from the same player. Kodi is minimizing and MPC-BE is being loaded fullscreen. Nothing special is happening. Are you using the newest build of madVR? There was a bug with SDR playback that was fixed with the last update. Are you mixing 32-bit Kodi with 64-bit MPC-BE? That could possibly be the problem.

You really should be using Kodi 17.6. v18 is not even at Beta status yet.