BBM Multiple Chats for Same Contact

I have recently purchased a new BB 9800 and have moved all data from my old BB Storm including my BBM Contacts. Now on my 9800 I see multiple chats from the same contact in the Chat option from BBM. I have tried removing BBM and loading it again several times but this doesnt fix the problem. This is really annoying ...... Can somebody please help .... :confused:

Do you have BBM set up to save chat history?

It may be that it is seeing old chat history using the old PIN number in the directory.