In the image texture node that you have plugged into the Metaliic input of the Principled BSDF shader change the Color Space option from Linear to Non Color.

In the image texture node that you have plugged into the Metaliic input of the Principled BSDF shader change the Color Space option from Linear to Non Color.

Edited after reading Nathen's comment below :

I'm pretty sure it didn't used to be like that. I'd love to investigate that file, it's hard to imagine that's not a bug.

I did a quick check and the change happened somewhere between Blender 3.3.1 and 3.4.1 .

Gif below is Blender 3.6.1 LTS :

Blender file with packed image texture: https://blend-exchange.com/b/j6Kvwmyo