The ability to keep comments private, either as notes to oneself or until the comments are completed, is a good feature in the Draft and Review spaces, but we are clearly seeing users who either forget to share or are unaware that they need to share in order for the other members of their team to see their input.
A warning upon screen exit that the author has unshared comments and an offer to review them would be helpful, as would a more clear visual distinction between comments that are public and comments that are private.
The "Unshared" label is fine and is arguably all that is necessary, but frankly, I'd either add a light red background or change the border to red to clearly designate the fact that something is different/incomplete about unshared comments.
Thanks.