Seeing the same thing. Started for me around October 14th.

The format suggested by Nobitahuang seems true. From the documentation example, it only seems needed on "some" ids. Specifically, for ids of type inAppPurchasePrices https://developer.apple.com/documentation/appstoreconnectapi/managing-in-app-purchases#Update-in-app-purchase-prices ... "manualPrices": { "data": [ { "type": "inAppPurchasePrices", "id": "${prices-id}" }, .... "included": [ { "type": "inAppPurchasePrices", "id": "${prices-id}", Adding the id inside the ${} literal works in Swift string interpolation "${\(inAppPurchasePricesId)}"

Also started seeing this around 2025-09-05. Using the manualPrice id returned from a previous relationships/manualPrices result. Error: Request https://api.appstoreconnect.apple.com/v1/inAppPurchasePriceSchedules failed with status code 409. Related response error(s): The request failed with response code 409 ENTITY_ERROR.INCLUDED.INVALID_ID The provided entity id is invalid. The provided included entity id 'eyJzIjoiNjQ1MTIxNzg3OSIsInQiOiJVU0EiLCJwIjoiMTAwOTQiLCJzZCI6MC4wLCJlZCI6MC4wfQ' has invalid format).