Energy conservation and/or specular term broken in PBR shaders

Even when using diffuse materials (like in https://www.kdab.com/qt-3d-animation-easter-teaser/) there is still a strong (and clamped) specular component at grazing angles such as on the silhouette edge of the egg.

This seems to be because the geometric factor is hard-wired to 1. Really even for an implicit geometric term it should be set to the same value as the denominator otherwise at grazing angles the vDotN factor gets very small in the denominator making the specular term blow up.