In the Post Check-in offer campaigns, the double points/rewards are rewarded based on the receipt time. So, if a campaign has already ended (on the end date set) but is active, then the guests will be able to earn for the same date purchases even if they scan the receipts after a few days (abiding by the loyalty criteria).
For example, a double points campaign was only valid for 16th (end date is set to 16th) but is still displayed as active. So, if the guests scan the receipts dated 16th on 19th, they will be able to earn the double points for the purchase against the promotion active on 16th.