handleCheckoutCompleted marked the payment 'completed' BEFORE activating the
subscription, but the idempotency guard keys off payment.status === 'completed'.
So if activateSubscription threw after the payment was marked completed, the
Stripe webhook retry would hit the guard, skip activation, and leave a
paid-but-never-activated subscription.
Fix: activate FIRST, then mark completed — a mid-activation failure leaves the
payment 'pending' so the retry re-runs cleanly. Guard activateSubscription with
an idempotency check (return early when already active) so a retry after a
successful activate but failed mark-completed cannot re-fire revenue events
(PostHog subscription_activated + Meta CAPI Purchase), re-consume referral
credit, or double-insert Full-plan brands. Admin manual-activate already
pre-rejects 'active', so legitimate first activations are unaffected.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Semih Yesilyurt
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