Visible fireflies using object's Texture Coordinate

Question

Making a simple procedural metal shader using a Noise Texture node linked to a Normal Map effect from the object's Texture Coordinate, I've come across this particular issue:

When I change the Normal Map value there's a very visible firefly that appears in the mesh, affecting the texture in some particular areas.

My first thought at this was that I had a Face Orientation or Duplicated Vertex issue. But to my surprise, all the Face/Vertex Normals seems good, and there were no duplicated vertexes.

See mesh analysis:

My node setup:

At this point, I knew that this issue went far beyond my acknowledgments, and this is what I've got so far.

Objective:

• Find the property or the mistake I've made that brings this particular issue.
• Notice if this is a Texture Coordinate bug from Blender with no troubleshooting so far.

Things I've noted:

• When the Normal Map value is 0 this issue disappears.
• All mesh normals are facing their correct direction.
• There's no duplicated vertex or faces.

Rules:

• This shader must be procedural for further use in different objects.
• Texture coordinate must be plugged in Object input.
• No UV maps dependency or mesh wrapping.

Extra points for:

• An alternative solution to make this procedural shader with no UV map or not depending on the object's Texture Coordinate.

Thanks in advance for your help!

Edit: here's the original .blend file