VDB Volume Grid and Deeps

[TeaspoonVFX]

I'm sure that I'm overlooking something. I've loaded in an OpenVDB sequence in the volume grid. Renders nicely. However, I'm not getting deep data when rendering out to DeepEXRs. Is there something I am overlooking? The VRayFog plays nice with Deeps, so, I would assume that other volumes can be rendered to deeps.

What am I missing?

Thanks!