We're testing Shopify app billing for a new app we're developing, and saw some disturbing behavior in a recurring+usage app subscription (recurring_application_charge): when the app current billing period ended, the balance_used amount did not reset to zero. The subscription is still reporting usage charges created during the prior app billing period (this queried just now, on 2023-04-18):
Per the subscription info above, the app billing period ended on 04-14. The last usage charge for this subscription was created on 04-05. The update on 04-17 was increasing the usage cap via the Shopify UI.
Why would this happen?
This is a Test subscription in a development shop - are Test subscriptions known to not behave correctly per the API documentation?