Hi, thanks for posting. You are using V-Ray GPU is this correct? I am able to reproduce it with GPU but please confirm that you are using GPU as well. I will investigate the issue further and get back to the thread.
I usually use VrayEdgesTex in a separate VrayBumpMtl after the main VrayMtl. Makes it easy to control without interfering with other bumps or normals (esp when you want to use it with multiple materials to apply it to a whole object) and clear that it’s a special effect you are using. Might be a suitable workaround.