Wrong SN at inventory material transaction

An inventory material transaction was not posted to Install Base because of the inventory_item_id; a user made a receipt of two serial numbers as the same item id, but one of them belongs to another item. I can validate the transaction at mtl_unit_transactions and mtl_material_transactions; I got no transaction errors, the app just did not do it.

What do you suggest to do in this case? How can I cancel or reverse the wrong transaction, and then transfer each serial number individualy with their own item id in order to synchronize them?

Also, what can I do to prevent users transact receipt from serial numbers which already belong to other item?