Same issue here. After adding IAP versions to a review submission via the App Store Connect API and then deleting those reviewSubmissionItems (DELETE returned 204), all 7 of our in-app purchase versions stayed in READY_FOR_REVIEW without belonging to any submission. Game Center versions deleted the same way went back to Prepare for Submission; the IAP versions did not. Now POST /v1/reviewSubmissionItems returns 409 STATE_ERROR.IAP_NOT_SUBMITTABLE ("Only versions in 'Prepare for Submission' or 'Developer Rejected' state can be submitted"), POST /v1/inAppPurchaseVersions returns 409 STATE_ERROR.ALREADY_EXISTS, and in App Store Connect each IAP shows "Ready for Review" with "Add for Review" disabled. Filed as FB25005666. Tip for others: when building a submission via the API, add the IAP items last, and never delete an accepted IAP item; there is no way to reset its state yourself.