Seems photoshoped to me. The nut is fairly bright red and the washer under it looks hardly impacted. Maybe a picture of some issues but the bright coloring was added.
I've seen this several times over the years, I think it's photoshopped; greatest heating and therefor red would be at place of highest current density.
I'm in the fake pic camp too . I am guessing that nut was heated with a torch from the bottom or with an induction heater . no way that steel is that hot without other stuff around being more compromised