Flag a review card that has no due date so its owner can see the deadline gap before asking for a review.
Message release owners about undated review cards before handoff.
Your card owners see the review work missing due dates before the weekly handoff, with links to the cards they need to update.
Label undated review issues so delivery owners see the gap.
Your Friday review queue shows which cards still need deadlines, with a label and note to help owners follow up.