Using Zotero Standalone with Word 2013 Preview with IEEE style.

I write some text, reference something, go a few lines below, add bibliogrpahy, go back to that initial text a little before the first reference and add a different reference...

And I get duplication.

Example:

Two foo [1]Foo bar[2]

Bibliography
[1] A. J. Boersma, K. L. Brain, and H. Bayley, “Real-Time Stochastic Detection of Multiple Neurotransmitters with a Protein Nanopore,” ACS Nano, vol. 6, no. 6, pp. 5304–5308, 2012.
[1] K. Aberer, L. O. Alima, A. Ghodsi, S. Girdzijauskas, S. Haridi, and M. Hauswirth, “The essence of P2P: A reference architecture for overlay networks,” in IN P2P2005, THE 5TH IEEE INTERNATIONAL CONFERENCE ON PEER-TO-PEER COMPUTING, 2005, pp. 11–20.
[2] A. J. Boersma, K. L. Brain, and H. Bayley, “Real-Time Stochastic Detection of Multiple Neurotransmitters with a Protein Nanopore,” ACS Nano, vol. 6, no. 6, pp. 5304–5308, 2012.