A long shot but is it possible you have the same “screw shorting tracks” problem that I had here https://opensprinkler.com/forums/topic/opensprinkler-firmware-2-1-0-beta-major-upgrade/page/5/ ?
Just in case there is any confusion, NTP doesn’t care about time zones, it just delivers Universal Time (UTC). The local device then corrects that to local time based on the location or time zone that has been set. When I want to test if NTP is working on something I will set the last digit of the minutes incorrectly and then see if those correct when the NTP update happens.