When reviewers have completed their review, and the request is in REVIEWED state (but not yet returned), the reviewers are still able to change their votes. This is required so that in the consolidating phase, reviewers can discuss and potentially change their minds about how they voted. However, if they change their vote to undecided, the request stays in REVIEWED state, and their individual review is still considered to be complete. We should prevent this so that a request can't be returned with incomplete decisions on files.
When reviewers have completed their review, and the request is in REVIEWED state (but not yet returned), the reviewers are still able to change their votes. This is required so that in the consolidating phase, reviewers can discuss and potentially change their minds about how they voted. However, if they change their vote to undecided, the request stays in REVIEWED state, and their individual review is still considered to be complete. We should prevent this so that a request can't be returned with incomplete decisions on files.