The Volumetric Exponential Height fog also works in VR with UE4.26. See here the fog swirl in the foreground:
Exponential Height fog and Volumetric clouds use the volume materials.
Removing the volumetric advanced Output also doesn’t make the clouds visible on both eyes. So I would assume the problem is not with the volume material itself.
I’ve looked into the Volumetric Cloud Component C++ file to maybe fix it, but I have no idea what’s going on or where the problem might be. I thought of looking into the source code of the 4.25 plugin version, but I can’t find the code.