A useful handoff would clarify whether the enquiry was sent and leave the buyer with a traceable next action. Jin can replicate that manually with dated notes.
I’d avoid prescribing one fixed timeframe because advertiser practices vary. Jin can set a personal cutoff based on travel plans and the strength of alternatives.
If a duplicate remains live after another version is said to be unavailable, keep both records. The contradiction itself is useful evidence about freshness.
There is also a risk of reporting two genuinely different units as duplicates. Include the shared evidence and the uncertainty rather than making a stronger claim.
A reasonable matching rule is exact photo sequence plus equivalent layout and description, then confirm with the advertiser. No single clue should decide it.
When forwarding a listing or discussing it with someone else, include the observed price and date as well. A bare link may later show different information.