I have this same issue with Simple Automation Rule 1.2 turning a light on at Sunset and off at Sunrise. It appears to be a bug.
The light will not turn on or off as long as the "Offset in minutes" is 0 for both Sunrise and Sunset. There are no scheduled jobs after pressing Done.
As another data point:
A rule turning off a switch at sunset in Simple Automation 1.1 worked tonight for me.
Also, a rule with a restriction of sunset to sunrise in SA 1.1 also worked.
I am on 2.3.4.114
I was trying to be helpful, saying that it worked in SA 1.1.
The only way to tell, far as I can tell, what version of SA the app is running in is to look at the Device Details. True?
edit: I found this in the app status page, so I guess that's another way:
The rule is using SA 1.2. I am using the latest update 2.3.4.114 . This same work-around of adding -1 to the offset was required to make it work before the update.
I was just able to duplicate this. I created a new SA 1.2 rule. No scheduled jobs with just sunset and sunrise. The two scheduled jobs show up when sunset AND sunrise are offset by -1. If only sunrise is offset, then only sunrise is scheduled. Running latest hub firmware.
I take it back. It worked tonight at sunset. Even without the scheduled jobs on the gear page. So, I better bow out of this one, lol. Sorry 'bout that.
Sunrise and sunset without offsets don't use Scheduled Jobs at all, simply system events seen in Event Subscriptions. The hub sends these events daily.
I'm not seeing any problem with these. Be sure you have Logging on. See what the logs say.