This doesn’t seem to be a bug. I found that I can’t control the color gradient and opacity gradient in the gradient tool alone. In krita, the color gradient will be affected by the color opacity. Especially when the opacity at one end is 0, the influence of the color on the gradient color will disappear. I tried to set multiple color insertions, but still failed to achieve the desired effect, It would be useful if we could add a separate opacity controller like photoshop.