Check your local Circle K and see if the portal is still there. Chances are, it’s not. If you have a key to one of these portals, you can check by clicking on it and see if it takes you to the portal or empty space. There are also reports that Zipcar portals are vanishing as well. Andrew Krug, Niantic’s Global Community Manager has confirmed that the promotion has ended. As well as, Zipcar promotion ended years ago. So portals vanishing may just be a clean up as well at this time.
The Circle K app was also updated on iOS and no longer includes the Ingress deals. The passcodes obtained do still appear on the home screen though.
The original post about the Circle K partnership was posted just a little over a year ago, so this seems about the right timing for this partnership to end. You can see that post here: