A design change has occurred in the way that Service Desk 12.0 (and above) handles inbound email when "%Customer" data is provided, but not able to be matched to a Contact record.
Example of Differences:
Inbound email with an "invalid" "%Customer" value and "VALID" "%FROM_MAIL" of an Analyst.
Service Desk 11.2: A warning sent back, but the Call Request is created with Analyst "from" details.
Service Desk 12.5 CA SDM: Call Request is not created. Error sent back that the Affected End User is not found.
"AHD58009:Could not create Request. Reason: INVALID - AHD03075:Required attribute is missing."
The introduction of Multi-Tenancy required a design change of the inbound email rules. The opportunity arose to address an invalid behaviour for non-tenanted sites at the same time.
Prior to Service Desk 12.0, the Customer (Affected End User) was set to log_agent by default.
It was overwritten if a valid value for "%Customer" was provided.
From Service Desk 12.0 onwards:
For non-multi tenancy sites, the behaviour documented above for 11.2 was leading to incorrect SLA counts against the log_agent and customer.
For multi-tenanted sites, continuing with the 11.2 behaviour may have led to a conflict between fields due to the tenancy requirements.
The design decision made was that from 12.0 onwards, the Affected End User (Customer) value would be set to log_agent only in the case where no %Customer value is provided. In all other cases, an error is returned, alerting to a possible conflict or missing information. It is no longer the case that in the above scenario a ticket will be created.