I have a screencast but its 217MB so way too big to email - how do I get it to you?
There is an enabled Scheduler event that shows 23:21 to next event that I minimise at a screen clock time of 20:43. When I restore the Scheduler from the dock the time to next event is still 23:21, then there is a burst of log timer activity and the countdown drops abruptly to 23:17.
GS is open and minimised when this happens.
I had a half way pleasant surprise today when I left GS open and GS Scheduler open (not minimised) overnight last night. Although the Mac screen shut down due to inactivity when I went back the Scheduler countdown clock was correct, so problem is only when application /scheduler are minimised.