It has been noticed that when a user has an invalid email address in a user contact. An example would be lpower@domain (i.e. no domain suffix). Instead of MfNE ignoring this contact, it appears to try to find a match for it in the Domino Directory. In one case it created a local contact in Outlook for a user called John whose surname was different from the John in the Lotus Notes contact.
What was also seen was that it was matching against the first instance located in the Addresstranslation.tsv which fit the user name.
so James@Company would be matched to the 1st James that appeared in the TSV.