I have my whole scene contained in a big cube, and the cube's shader has both volume scatter and volume absorption (which are mixed with an add shader). So the whole scene has haze.
Then, where light is emitting from some conical lamps, I have some invisible light cone meshes, and their volume shader has a stronger haze effect, about double that of the room.
Either haze effect works fine on its own. But when I enable both of them, some haze from the cone lights appears to show through solid objects. But not consistently... like in the pic below, areas near the camera don't have the issue while areas a bit further away show it.
What's the cause, how can I fix it?
See the screenshot below to see what I mean.