Common mistake on IBL specular in pbr.hlsl

[x380kkm]

I found this issue in another technique
And it also appears here.
float3 specular = prefilteredColor * (F * brdf.x + brdf.y)
should be changed into
float3 specular = prefilteredColor * (F0 * brdf.x + brdf.y)

[Atrix256]

oh, thank you!