I've seen this before with other file based footage other than sony. Are you sure you have all proper sony plug ins loaded? THat has been the root cause for m green clip experience in the past, not having the necessary plug in loaded, that is.
If you have only a few long clips to export for transcripts you can use Open in Timeline and drop the Timecode generator or the TimeCode Effect on the clips in their timeline. This will give you the correct burnt-in source time code and you can export to any format straight from this timeline.
But if you have a load of short clips to export this method takes too much time. We absolutely need a time code reader that reads source tc from the clips on our main timeline.