Record which revision of a proof was sent to the reviewer.
Email the current creative proof and note the revision sent.
Your reviewer gets the current image or PDF and a clear question. Your review card shows which revision you sent.
Record which creative proof revision went out for review.
Your team gets a dated record of which proof revision went to each reviewer, even as work on the board moves forward.
Mark the artwork revision handed to reviewers on its card.
Your review card shows the proof version your reviewer received, even if the linked file changes later.