My recommendation is to upgrade to 5.1(5) if running 5.1 on your sensors.
The 5.1(4) upgrade put in the new defaults for the new time changes, but there was an IDM bug where the old time changes may have been written as "user" configuration.
The 5.1(5) Service Pack corrects that IDM bug and ensures the new time changes will be used.
If running 5.1(4), 5.1(5), or 6.0(1) then execute:
show conf | begin summertime
It should show:
summertime-option recurring
summertime-zone-name
exit
exit
! ------------------------------
Followed by the rest of your config.
So long as nothing is between the "recurring" and the name, AND you are running 5.1(4), 5.1(5), or 6.0(1) then you are fine because it will use the new defaults for this year.
If it has anything between "recurring" and the summertime-zone-name then it may not be set correctly.
If running 5.1(4) or earlier, then upgrade to 5.1(5) and check it again. 5.1(5) will correct most mis-configurations.
If you are already running 5.1(5) or 6.0(1), then you will likely need to do some correcting manually.
1) conf t
2) service host
3) default summertime-option
4) summertime-options recurring
5) summertime-zone-name
6) exit
7) exit
8) yes to apply changes
9) yes to reboot
