If you have an Import Process with a Message Action of AutoFill Keyword Set, and a Keyword Type with a Date & Time Data Type is assigned to non-date field in an HL7 message, nothing will be stored in the AutoFill Keyword Set.
If a Keyword Type with a Date Data Type is assigned to non-date field in an HL7 message, a default value of 2000-01-01 is used.