Sometimes Grave Robber doesn't work - hard to narrow it down more than that. I know from Sir Ivan that with captions you have to manually enter the nest and turn on the captions track selector & I've seen this work sometimes, but not always.
Projects are NDA so I can't share for reproduction so I know this is not that much help. I would just say that Grave Robber needs a bit more work.
Pr 15.4.1 Windows GR is 1.0 I think - I've never seen an update