Address Book repeats contacts name

[montycat]

Does any else experience this? Some contacts, mostly my own, repeats my name. All I have for my own contact name is Monty. It is always changing to Monty Monty. I doesn't matter if I delete the first name or last name as it always reverts back to Monty Monty. Some other contacts appear as David David or Cindy Cindy. This happens on both my Macs. I did export my Address book from my iMac to my MBP. Thanks MC