When I click on the days of the next month (the gray one´s at the bottom) the date on the input is correct. But when I open de picker again the current date is one month ahead. The problem is easy to reproduce on the demo site.
Steps:
1 - Select January 2015 .
2 - Click on day 4 (bottom) of february.
3 - Open the picker again and the selected month is March.
Thanks! Great work.