i am working on project required some clouds and there is will be object moving through this clouds with fire

anyway my problem when i bring the cloud as vdb file and but them in front of TFD i lose the TFD shape and i get this kind of square around the TFD volume please take look to the image and i include the c4d file and you can of course make your own scene with vdb file in front of TFD volume.
Thank you in advance and sorry for bothering.