You're Welcome!
Yes, I'm considering if it's tangent related as well, if I create the cube in either Unreal Engine then export for Substance Painter, or create the cube directly in Blender and export for Substance Painter using the same process it works fine, the problem with this is it's not working for my regular workflow.
I create the Unreal Engine BSP geometry first like normal, convert the geometry to static mesh as I've done, and edit the geometry adding extra details in any other program first, and then I want to paint on it with Substance Painter rather than using the built-in painters in Unreal Engine, Blender, or Hexagon to finalize the basic process, this is one of the main reasons I bought Substance Painter to rapidly cover the paint aspects and as I'm working on some of my own levels and content for Unreal Tournament and will be later for my own games and art assets.
One thing I've also tried was to apply a Specular Channel and adjusted roughness all the way up, while bringing the Specular down, this brings the surface to a closer matte finish removing some of the reflective highlight effect, and if I switch to UV it locks the paint brush flat and I can paint on the surface, the problem with that is it doesn't solve the problem and it doesn't provide accurate results to paint normally by default, and you rely on extra tweaks that doesn't fully fix it so it's not a complete solution for a final product.