Why are customers still getting sale prices in my store?

Hi, I recently ran a sale for my store, which is now back to the normal price. But customers are still able to buy at the discounted price. How did this happen?

No, I did not use a discount code. I adjusted the price of the product itself, and after the promotion period, all the prices were adjusted back to the normal price.

For new checkouts now, no, it is the original price. I looked at the Conversion Summary. The customer came back from the abandoned cart email.

Could it be that they can still checkout with the discounted price?

As I said, the price is already adjusted back to the normal price, so my store does not have any more discounted prices visible.

If we use a discount code when the code expires and the customer comes back from the abandoned cart email. Will the same problem happen?