They just changed it today. Here is the email I received:
I am reaching out to you because you have previously completed a Papa John's shop or are currently scheduled for a Papa John's shop during 2018.
As of April 2018, we have put a new restriction in place for Papa John's. No person may shop the same location more than twice in a month. In addition to this, if you do shop the same location twice in a month, you must have at least a week in-between the shops.
Again, you can still complete five Papa John's shops per month; however, you must meet the specifications above. I know this is a change from the usual, as there were no limitations before.
Please let me know if you have any questions regarding this via email. I will do my best to respond in a timely fashion.