Wrong letters after reference year Endnote X7, Word 2013

Hi,

I use a customized version of APA 6th and I have a problem with ambiguous citations where the letter after the year is wrong.

Below I’ve pasted from the bibliography: in short Shi 2011, Shi 2013a, 2013d and 2013e. - Should obviously be 2013a, 2013b and 2013c.

Iv’e used the “Find duplicates” with great success but not with this one.

How do I “reset” the lettering? Update citations and Bibliography in Word 2013 does not change this. In the EndNote X7 window, in the reference list of that specific word-document, there is only these 4 articles from Shi et al.

Thanks in advance, Mikael

Shi, J., Knevel, R., Suwannalai, P., van der Linden, M. P., Janssen, G. M. C., van Veelen, P. A., et al. (2011). Autoantibodies recognizing carbamylated proteins are present in sera of patients with rheumatoid arthritis and predict joint damage. Proceedings of the National Academy of Sciences of the United States of America, 108(42), 17372-17377. doi: 10.1073/pnas.1114465108

Shi, J., van de Stadt, L. A., Levarht, E. W. N., Huizinga, T. W. J., Hamann, D., van Schaardenburg, D., et al. (2013a). Anti-carbamylated protein (anti-CarP) antibodies precede the onset of rheumatoid arthritis. Annals of the Rheumatic Diseases. doi: 10.1136/annrheumdis-2013-204154

Shi, J., van de Stadt, L. A., Levarht, E. W. N., Huizinga, T. W. J., Toes, R. E. M., Trouw, L. A., et al. (2013d). Anti-carbamylated protein antibodies are present in arthralgia patients and predict the development of rheumatoid arthritis. Arthritis and Rheumatism, 65(4), 911-915. doi: 10.1002/art.37830

Shi, J., Willemze, A., Janssen, G. M. C., van Veelen, P. A., Drijfhout, J. W., Cerami, A., et al. (2013e). Recognition of citrullinated and carbamylated proteins by human antibodies: specificity, cross-reactivity and the ‘AMC-Senshu’ method. Annals of the Rheumatic Diseases, 72(1), 148-150. doi: 10.1136/annrheumdis-2012-201559