Volumetric Fog Shadows Density

This is something that has bugged me for years but I’m not sure if there’s a setting I’ve been missing, just a rendering limitation for performance reasons or something about the physics of light through water particles that I’m misunderstanding.
The density of volumetric fog in shadow areas when cast volumetric shadows is turned on seems incorrect to me. It’s like the density is calculated in screen space based on the shadow, providing a sort of window through the fog to see the horizon. But then when you move through the shadow the density jumps up again as there is no screen space shadow to reduce the density.

Position A

Here the shadowing on the right is allowing better visibility on the pillar as expected but you can also see the horizon much clearer through the “window” of the shadow.
When you move the camera forward just past the pillar the horizon is hidden again behind the fog:

Position B

This seems incorrect as the density of the fog to the horizon at position A should be all the density of the fog at position B plus the extra for the distance back from B to A, not less density.

I’ve tested with ray traced shadows and mesh distance fields on/off and there’s no difference.

Any insights would be much appreciated.