User wants to process Item Receipt in a period where AP is already locked.
Since this is not posting to AP Account they are expecting to post item receipt in a lock period even if the role used does not have the Override Period Restrictions permission since Item Receipt does not post to an AP Account type.
It is currently by design that Item Receipt will not be allowed to post to an AP locked period when the role does not have the Override Period Restrictions permission even if it does not post to an AP Account Type. The system considers the Item Receipt as an AP-Type transaction.
Note: This is documented in Enhancement 417684.