What are this lines and how to clean it

When im painting im getting some gray lines on the paint.

lines on faces.blend (3.7 MB)

When i fill the color i dont get any lines

But when i paint with color with the brush i get those lines.

How to clean those gray color lines. Any suggestion. Thanks

Maybe this can help

Pack your textures before sharing your file, I don’t have any image file and here difficult to help