I have a question about the paint condition of this guitar.

Hello, I have a JP13 Mystic dream model bought a few years ago

Recently I found that only the color on the left side of the back space is some kind of gold-like color , unlike the rest

I have no idea if this guitar has been like this since I first got it or if it’s discolored over time

Does anyone have any information about this situation?

I don’t think it’s a major defect, but just curious.