We noticed that recently quite often when a new recurring charge is created, the return_url is called twice by Shopify, once with an 'accepted' status and once with an 'active' status. It used to called only once with 'accepted' status.
I'm wondering if this changed recently?
Interestingly, the second 'active' call doesn't seem to happen all the time.
Are you certain Shopify is making the GET request to the return URL twice? It seems strange conceptually to send the customer through a redirect to that URL two times consecutively. Do you have a request ID showing the beginning of the flow I can inspect to maybe see what occurred on our end?