Yup, some just take a while longer.
What matters is not if you bought before the deadline but if the posting date of the charge is before the deadline. I know I've gotten burned with
Amazon because I was buying something towards the end of a quarterly 5% but Amazon doesn't actually post the charge until it ships, which in my case was a few days later.
Assuming the posting date is within the timeframe, it's OK that the offer isn't showing up after expiration. I've had ones that I did just before the cut off disappear and then reappear once the system credited me the reward.