The difference is that the operator id is already configured the locale as en_AU and i am checking the application from IST timezone. so in the date picker the date is not setting default to Australia's date when the date changes in AEDT.
ex: 23/11/2016 is today's date after 6:30 PM IST if we check the date picker it is still showing 23 as the selected date instead of 24.
***Updated by moderator: Lochan to create new post from this reply; add category***
The locale setting at the operator level helps in representing the date/time in that specific locale.
For example, enter de_DE to use the German display mode for dates (DD.MM.YY) rather than the American mode ( MM/DD/YY).
And for your question, you are checking the application from IST timezone and when you are trying to select a date after 6:30 PM IST, and if that reflects the next day as en_AU locale is set, it confuses the user as his date & time are different than the one shown in the control, which he suspects as an issue & which is a major usability concern.