When you stand in a cloud RTX disabled it will simply disappear.
However, this used to be different with RTX enabled: you would still see the volumetric lighting.
This is no longer the case, now the cloud disappears but it looks very weird with RTX enabled since the volumetrics cut off and decrease immersion.
It would be great if the fog inside of clouds were to be visible when you are standing inside of them, hoping for this bug to be fixed eventually.