When creating a new Outlook contact, many people simply enter the contact’s name in the contact’s <FullName> field instead of entering the values into the individual fields that comprise the <FullName> field. In doing that, Outlook has to parse the value entered and <TRY> to determine what the actual values should be for the various individual fields (i.e. First/Last name etc). How Outlook parses the values also depends on the default <FullName> setting in effect when the contact is created.
Parsing of the <FullName> field also occurs when a contact’s name is imported into the <FullName> field instead of the individual fields with the primary difference being that the Outlook importer does not take the current <FullName> default setting into account
This video shows various examples of how the same contact name can result in different values in the underlying individual name fields.
See also
Understanding Outlook Sync Issues
Understanding Outlook FullName Parsing, FileAs and Sync’ing