Duplicate invoice

Hi ,

i have an issue where an invoice is getting posted to times

first invoice was in 2005 for say $100, ref 1234, vendor xyz, PO 123456

second invoice was in 2007 same $100, ref 1234, vendor xyz, PO 123456

I have a check the vendor master for the duplicate invoice and also in the MM side.

Only thing i feel this is happening is b'cos the first invoice is archived. Please share your thoughts

Thanks