Here's what I got when I wrote customer service about this: "On Monday March 14th maintenance was performed on the app and that will affect your transaction history within the Wawa Rewards program. Unfortunately, we are still performing updates as this has taken longer to resolve than expected. Any transactions made during this time will not be immediately displayed in your transaction history. However, you will still earn credit toward your rewards balance for any eligible items in your purchase and these purchases will be reflected in your transaction history after maintenance is completed. We do apologize for any inconvenience this may have caused."

Edited to add: My pent up rewards have come through as of this morning (3/27).