HyperPixel Color Banding on gradient images


I am noticing that the HyperPixel 4.0 screen is displaying some color banding when there is a gradient image. It is not like this when I see the image from VNC (to the Pi), or on my computer.

Simply looking for gradient images on the web can reproduce this. I have tried to change the framebuffer depth to 18, 24, 32, but none of it worked.