I had walgreens 10% back on my Freedom and 2 checking accounts that expired on Dec 21st. I used it on my freedom to buy gift card and it worked perfectly. Got an email few days later and credit posted after another few days.
I went ahead and used it on both my checking accounts 3 days before expiration date. No email so far. Just looked in the app under those checking accounts and that offer is now showing under expired offer. I guess no dice