The gradient tool creates a black outline on shapes that are placed over a shape that has a gradient. See picture attached. The orange circle under the emoji has a gradient. A black outline appears under the red heart eyes. When I move the gradient, I can see the black outline moving around. The black outlines created by the bug are circled in green in picture 1. The outline disappeared in picture 2 when I lowered the gradient.
Please note that the glitch only seems to affect shapes that have a shadow under them (hearts and pink patches) but not the white star and the mouth.
This is the latest version of affinity designer and I work on a macbook pro (catalina).
Thank you for your help,