Yep. Confirmed. The slots were renamed, and I assume that's why the attachments were renamed.
The paths point to the correct region attachments but the runtime doesn't support reading paths yet so it thinks the name is the region attachment.
Now how to fix this...
For now, ask your animator to try to export with the parts named correctly and avoid renaming slots (or make sure to uncheck the "Rename Attachment" checkbox whenever your animator renames slots).
To fix this in the shorter term, your animator needs to make sure all the attachments are renamed to the filename of the individual images (monkey-04, monkey-05, etc...). This is a bit of a pain, but the only other option might be to wait for the runtimes to support the path field.
We could fix the json manually but that'll just break again when your animator re-exports the json.
Ohh, but I suppose your animator could rename the image files to how the slots were renamed in the editor. It'll be a bit messy but I guess it would work with some extra reattaching that needs doing in the editor.