Thanks, but I wouldn’t describe this as stuttering. It’s more like a mild static crackle, and it “pops up” (haha) consistently in regions of quiet or near-silence. Interestingly, I don't hear it at all during a silent pre-roll of any duration. As dskelto and I both mentioned, you need to have the volume turned up to hear it—which is appropriate for the acoustic and vocal performances that I’m listening to, and not at all a special case. Those performances are much more common in “pure” DSD (since digital editing and mixing require a conversion to PCM).
That suggests IMHO that it’s something to do with how the Gustard is processing dynamics or transients at that level while in DSD mode. DSD works by signalling a change in frequency with each bit, and the popping might have to do with a problem in the transitions around a certain (low) threshold. That’s just my educated guess.
I doubt it’s a buffering or latency issue, as I can play PCM up to 768KHz without any problem, and DSD is being sent as DSD encapsulated within PCM (DoP) on the Mac. DSD 64 and 128 should use less bandwidth than that.
Also, as stated above, the company has apparently acknowledged the issue and has a fix. So fingers crossed.