There is a hidden -yet very handy- feature that provides an audit trail of a review. I think this should be available from the main review page (and also include all review events). I have seen many requests involving wanting to know if/when a user has approved a review (as one example) that would remove this sort of uncertainty by putting the audit trail as a prominent feature of the review record.
For those looking to see an audit trail (I don't think this has everything but does timestamp each approval), use this URL:
<collaborator server: port>/go?page=ReviewTimeline&reviewid=<review #>