vertex color and baking id map

Hi, i tried to testing to make color ID map. i have baked vertex color to image texture. than i connect backed image texture to bsdf shader and the output is with black outline on cubes. Is it a bug or my bad way to backing id map from vertex color? i don`t want to use substance painter to bakce id map. i want to make it in blender and than import to Mixer. Do U have any idea how to fix this issue?