addCalendar function calculates one hour less in DST server time
DateTime calculations using addCalendar function in DST displays an earlier date with one hour less in GMT. This occurs when months are added to the DateTime property.
Steps to Reproduce
Use the DateTime.addCalendar() function to add the number of months to a date.
This behavior is as per Pega product design. The time zone in the Operator Work tab was set to Europe or London time zone.
The Europe or London time zone is equivalent to GMT during the normal time period. After DST transition, offset of Europe or London timezone is GMT+1:00.
The addCalendar Rule Utility Function (RUF) provides formatted DateTime in GMT.
If the input date is 3/27/2017 (dd/mm/YYYY), the date after adding a month is 4/27/2017. On formatting to GMT, the date in DST is 4/27/2017.
Offset is GMT+1:00 (BST= GMT+1:00) and the resultant DateTime in GMT is '20170426T230000.000 GMT'.