INVENTORY_REVISION_CONFLICT
The mailbox claim cannot use the supplied inventory authority: the inventory revision changed before the claim could commit.
Classification
Application code. The wire value and spelling remain the same in every language. A registered code does not establish that its feature is active in every deployment.
Handling
Inspect the authoritative inventory and persisted grant/receipt. Resolve capacity or state conflicts without changing the grant identity. An uncertain response is not permission to issue the reward again.