Rightjs Calendar - bad display of the next/previous month

The error consists in bad display of the next/previous month in the following situation:

Step 1: Click to calendar input to open the respective calendar, and you will see the last saved month (or current if no value in the input).
2. Go backward/forward with previous/next buttons to navigate to another month and/or year.
3. Remember the month where you are in this moment. Without check any date, click on any area around to hide our calendar.
4. Now open again the same calendar and you will see the last saved month (or current if no value in the input).
6. Click on previous/next button and here is the error, the displayed month does not follow the order but is displayed on base of the month where we are stopped at 3rd step.
Note: this occurres when some date(month, year) different from current is selected.

Thanks.

-- Darii Denis.