Diffuser appears to have been burned on edges.

I have a UH65JS8500 SUHD. Areas of the screen are darker and, white lights are showing around the edges. I saw on youtube a Samsung like mine with the same issue, they removed the diffusers and found burns on them and melting. What is the costs of replacing the diffuser panels. Apparently Samsungs can overheat causing this and it may be from setting the backlighting to highest setting causing heat build up.