Armature deform renders on one computer, but not another

Here’s a weird one, and I’m looking for leads. A student sent me an animation which has armature and shape keys on it. They said the shape key animation was rendering, but the armature not. Opening the blend file on my computer, it runs and renders just fine in both, and due to COVID, I don’t have access to their computer. We’re both running MacBooks, though.
I could imagine if they had the armature turned off, or weren’t in pose mode, but they say it works fine in the preview window, as it does for me, but just won’t render into final frames. I’m guessing that any settings they’ve got on their system that would affect this would be saved in the file and be identical on my system when I open it, so I’m stumped. Any ideas on what could be causing this?

Sounds fishy. Get them to give you a viewport render and a screenshot of their modifier settings, or a screen capture of it running with the whole Blender interface (with modifier settings, the main thing here is seeing that the armature is enabled in both render and preview.)

There’s really no way to imagine this happening that wasn’t a Blender bug. If it’s a Blender bug, the temporary workaround would be a viewport render anyways (or alembic export maybe.)

Thanks! Yes, that was my thinking as well. They say they’re doing a viewport render for their final and it’s working there. Really baffling.