The "shadow" often comes from how the HUD transparency or background is rendered, try to check if the shadow persists when the HUD is hidden. And try switching to Active Desktop (Screen) recording mode. While less efficient, it captures the frame buffer differently and often bypasses HUD hooking bugs.

Motion Boost relies on your CPU and GPU to process and upscale video, especially with higher resolutions like 1080p. Even if your PC is powerful, the software might not be fully utilizing your system’s resources, especially if the Motion Boost effect is too demanding on the hardware for large files....