PCSS soft shadow disappears in specular reflection when light intensity high

[dmnsgn]

The soft gradient disappears when mixed with the color and the sampling pattern becomes more visible.

Results above with a dir light at intensity 10 and a floor (roughness: 0.15, metallic: 0.75).

Clamping the D term of the brdf to 0->1 helped but that's not physically correct.

[dmnsgn]

To note three.js implementation examples shows the same signs:

[dmnsgn]

This is the assumed behaviour for high reflective surfaces (eg. big metallic).