We see the same issue in production. Did you get any response from Apple, or have you gained any helpful insights?

The situation is even worse. On https://developer.apple.com/documentation/sign_in_with_apple/processing_changes_for_sign_in_with_apple_accounts Apple is stating, that "account-delete" is sent as a type in case a user deleted his or her apple id. The event type we actually saw in production was "account-deleted". While we of course can't be sure if it is actually a typo, or some additional undocumented event type, I assume that this is a typo in the documentation.

Is there any official statement from Apple stating that the free trial features they are using themselves are not available to 3rd party developers?

We have the same problem. It must have started about 8 hours ago. Does anyone have any idea what the problem is? How can it be solved?