Flickering VDB issue

hey everyone!

I’m trying to create a storm environment in UE. Using Ultra Dynamic Sky plugin and imported some stock vdb clouds too. When I place the imported vdbs on top of each other, I’m getting weird flickering effect. Besides that vdb clouds are not blending with clouds of Sky system and any UE light doesn’t seem to affect the VDBs once I scale them up.

I captured my screen. Please take a look at here.

Any help would be appreciated. Thanks