My guess is that FT clocks are at set at one of the US timezones then add/subtract for your preferred timezone to display local time eg if it's 09:00 gmt then it is 05:00 EST (-5 hrs plus 1 for DST). But they are adding 5 hrs to put you back to GMT without accounting for the DST change overnight. This sort of thing is usually covered by a tick box option somewhere to allow for DST differences.