Unable to select start and end date.

[Kratika-Synclovis]

On setting start and last date, when I am picking start and last date of the month, it is not selecting. In addition to this, when I am selecting 3rd day of the current month, it is showing position as 5. And same problem with other dates. If I am setting start and end date as +1 and -1 respectively then it is working but then it is showing last month also as enabled. And that date is also not picking. What should I do?