It’s possible you suddenly discover a store in your wallet you didn’t add. This store has a different icon than other stores and when you open the card you see points instead of stamps.
This is a group card, an additional cool feature to save for more discounts.
When a mall or a group of stores promote Stampwallet together, you will automatically are added to a group card. When you save in store A and B of group X, you will get your normal stamps on card A and B, but also receive 2 points (or more) on card X.
With those points, you automatically save for cool extra prizes. They can change every week and will not influence the stamps on card A and B when redeeming. So extra and more prizes!