stripe_subscription_incomplete
Stripe answered with a subscription carrying no item billing period, which the pinned API version places on the items. Confirm the account's pinned version matches the adapter's - a locally guessed period would disagree with the invoice.
Problem shape
Every non-2xx response is an RFC 9457 application/problem+json body. The type URI below is stable and machine-matchable, so branch on the final path segment (the code) and treat the status as redundant confirmation. See the error-handling guide.
{
"type": "https://docs.vocapable.com/errors/stripe_subscription_incomplete",
"title": "…",
"status": 502,
"detail": "…",
"instance": "/v1/…"
}