Cdt Casting is converting the date time to system timezone

Json response is giving date time value as output. We are casting this output to a cdt field (date time field).
We are using a!fromJson to convert the json response and map it to cdt.
The issue is casting is converting date time value to system time zone which is EST.

Example:
Json response is:"LAST_MODIFIED_DATETIME":"1\\/13\\/2017 2:52:00 AM"

a!fromJson("LAST_MODIFIED_DATETIME":"1\\/13\\/2017 2:52:00 AM").LAST_MODIFIED_DATETIME gives
1/13/2017 2:52:00 AM

After casting to cdt the value is :LAST_MODIFIED_DATETIME=1/12/2017 9:52 PM EST

Is there a way we can get the original json output as cdt output?
Why is the cdt altering the value and is there a way to stop the conversion .

OriginalPostID-257592