Flatpickr is using the Date object internally and that always uses the local time of the computer as the default time.
I m using Flatpickr version 4.6.6
Is there any way to set given time zone for flatpickr?
According to their issue tracker on the matter, it is not currently possible to set timezone with flatpickr. So you stepped into one of the component's limitations
I suggest you join the people voting for this to be built, or try using another gadget as a replacement.