As per the reported behavior, in PRPC 6.x ,when Date property is assigned to a DateTime property the difference of time zones is appending to DateTime property which is not the expected behavior. Ideally, it should append T000000.000 GMT value to the Date value as observed in version Pega 7. This is expected behavior.
If you observe a time difference, in a Data Transform, add the time difference which is equal to amount of time between operator timezone and GMT.
For example: 5.30 hours is the difference between IST and GMT. Add 5 hours 30 minutes to selected time before assigning it to Date property.
The workaround suggested will work in this scenario, but the daylightsavings time duration needs to be taken into consideration for EST timezone. But also the issue is that, even in Pega6, the Datetime property value has a timestamp of T000000.000 GMT which is the same in Pega7 . But somehow, when it comes to the UI, in Pega 6 the correct Date is displayed, but in Pega7 the date is always 1 day behind due to the GMT-EST conversion and with the same Operator Timezone/Calendar values in both Pega6 and 7.
Any clue on why the GMT-EST conversion is not happening in Pega6, even though the Datetime value is with timestamp of T000000.000 GMT.