I tracked it down to the edge split modifier on the model. Applying/removing/disabling that fixes the issue.

I'm not in a position to debug this properly so there won't be a fix for a while. My instinct is that it's a bug in Blender 2.80, as modifiers should be transparent to export scripts.

Whoops. I'll get this fixed when I'm next able.

If you could have reported this at a time earlier than one hour before the release of Blender 2.80 that would have been great. Please upload your blend file and I'll take a look.

Please paste the output of the console window into a reply. You can turn this on from the Window menu.

If you are using 2.80 then I just fixed an issue related to shape keys, so please update to grab that change.

But this looks like a completely different issue to me. Are you compiling the SMD and VTA exported by Blender together?

Given how much detail there is in this model, this might even be a limitation of the Source engine...

Fixed it, download the add-on from GitHub again.

This is broken in 2.80, thanks for noticing it! I'll get a fix onto GitHub soon.

This is a bug in the exporter related to moving the root bone of the model. It's already fixed and awaiting release once Blender 2.80 comes out.

Until then, you can work around it by exporting the mesh first, then the animation.

https://gtm.steamproxy.vip/groups/BlenderSourceTools/announcements/detail/1718585269185629423

Compile the SMD and see if it looks the same. Let me know if it doesn't.