The bug is in front of the keyboard.
A user can create as many duplicate materials as he want.
the characteristics/field values of a material master are not validated by SAP to identify if a material is a duplicate to another material, if you need it, then you have to develop this logic yourself
by the way, please do not use words like ASAP, each question is equally important. the SCN platform is not a service that you bought together with your SAP system, you may confuse this with the service marketplace https://service.sap.com/notes. SCN is a community were people help people, so you should not urge voluteers.