Hi everyone. Is it normal for slices to take substantially longer to be created if they're made from a derived field rather than an intrinsic one?

Specifically, I'm having an issue creating an axis-aligned slice using the divergence of the velocity field. It's taking around 6.5 minutes just to make the slice, whereas if I use temperature or density, it takes around 10 seconds or so for the same dataset.

I also notice that the amount of time it takes is not dependent on the number of processors I'm using. I've used 1, 12, and 24 processors, with identical results, even though I'm calling enable_parallelism(), and I can see that all the processes are running.

I read in the docs that slice operations aren't generally done in parallel, but in this case it seems that maybe it would be beneficial. A similar operation in VisIt completes much faster, so I'm wondering if I've misconfigured something, or if there is something I can do to speed things up.

I'd appreciate any thoughts anyone has on the subject.