Mtoa Volume_z AOV coming out black on batch render

[jakob.littlewater]

Hi there.

I'm trying to render out the volume_z AOV on mtoa 3.1.2.1. In the IPR it renders fine. I can save it out to an .exr which works fine, too. When I do a batch render, the AOV comes out black with no info in it and few kb of data only (all frames the same size). The AOV just doesn't get written. With merged AOVs it just doesn't include the volume_z at all. My workaround now would be to do a sequence render locally which saves the AOV out fine, but I cannot put the job on our farm which sucks. Any ideas why it is not saving out that specific AOV? All others like volume_opacity etc. save out fine. It's just the volume_z.

Cheers