https://userapps.support.sap.com/sap/support/knowledge/en/3295355
3295355 - Messages "MMPUR_REQ_COMMON 095", "MM_PUR_REQN 003" and "MM_PUR_REQN 002" cannot be set to...
Even though these messages have been configured to not be displayed, they still appear in ME51N transaction or in the Fiori apps (i.e. Create Purchase...