Cemu

This minor issue probably relates to an incorrect texture addressing mode when upscaling.

The Breath of the Wild loading screen, where the upper part of the screen is bright and the lower part black shows the problem.

In Direct3D terminology (I'm not familiar with OpenGL or Vulkan), there are several texture addressing modes, see https://docs.microsoft.com/en-us/windows/uwp/graphics-concepts/texture-addressing-modes
If Cemu is using the "wrap" mode that would explain this issue. Using either mirror or clamp modes instead should resolve it.

To reproduce:

• Set Cemu to Vulkan, full-screen mode, with emulated resolution less than Windows desktop native resolution. For example 1280x720 with 3840x2160 desktop/monitor. In full-screen mode, Cemu scales up the image to the Windows desktop size instead of changing video display mode to match the emulated resolution.
• Launch Breath of the Wild.
• On loading a saved game the loading screen appears. There is a light horizontal line at the bottom of the screen. That's because due to filtering, the top of the texture has wrapped around. Similarly, when the loading screen first appears and the upper bright band moves in from the right, you can see a light vertical line at the upper left edge of the screen.

I didn't see this issue with OpenGL.