I am having this same issue on my M1 Macbook Pro 14". I am also experiencing occasional flickering with mouse movement in GPU mode. The flickering appears to switch between the visual difference of GPU and CPU modes. Everything looks slightly desaturated in GPU mode all the time.
I should mention that I only notice this visual difference on my external monitor that's plugged into my M1 Macbook Pro via HDMI cable. Monitor is a BenQ PD3200U-T set on sRGB color mode.
I am having this same issue on my M1 Macbook Pro 14". I am also experiencing occasional flickering with mouse movement in GPU mode. The flickering appears to switch between the visual difference of GPU and CPU modes. Everything looks slightly desaturated in GPU mode all the time.
I should mention that I only notice this visual difference on my external monitor that's plugged into my M1 Macbook Pro via HDMI cable. Monitor is a BenQ PD3200U-T set on sRGB color mode.