In internal support ticket https://secure.helpscout.net/conversation/2680320821/27602 an issue occurred with two attempts for a first payment for a new Restrict Content membership (probably by using the browser back button).

The 2nd attempt was successful and the subscription/membership was activated, but when the 1st attempt later expires, the subscription status was updated from "Active" to "On Hold" — resulting in the Restrict Content membership also being updated from the "Active" to "Pending" status.

It seems this is caused by a little bug in the core subscription module, as the SubscriptionStatus::ACTIVE === $subscription->get_status() check should use the !== operator: