As a way to monitor review form conversion and make sure we capture as much content as possible in the event of a reviewer having an issue with the review form we capture partial review content.
This is solely for internal monitoring purposes as these reviews cannot be published since they are (a) incomplete and (b) lack verification and approval from the user (since they did not finish the form and submit their review).
Last week when we rolled out a performance improvement to the automated review manager some partial reviews appeared as 'pending' reviews.
This issue should now be resolved but please feel free to reach out with any questions or if you are still seeing a partial review in your vendor dashboard.
We apologize for any confusion this may have caused.