To reproduce this:
- download this project
- open it with Unity 2019.3.0b4
- open the SampleScene
- notice that the particles are grey
- if you go into the lighting settings and turn off fog or change it to linear, notice that the particles should be red.
- same does not apply to the cube, just the particles
- if you zoom out from the cube, you will notice that the fog has an inverse effect on the objects: the cube becomes grey and the particles become red.

This only happens for VFX Graph particles, and not for Shuriken particles.

Reproducible in 2019.3.0b4, 2020.1,0a5, 2019.2.0f3