I have been using automations with sunset/sunrise triggers for a long time and they have worked flawlessly until mid Jan where the sunset/sunrise time stop updating daily. I’m on stock firmware: 000.034.00011
I have been exchanging with the Smartthings support for a couple days now and it is not progressing well. But, interestingly, they made me change my home position to another time zone then back the correct position, which I did on Saturday. The sunrise/sunset time got updated to the correct time for that day, but since, the time is stuck (no daily updates). I believe also creating or updating an existing automation (like adding an action) with sunset/sunrise trigger will cause the time to be updated.
I moved all my sunset/sunrise automations to smart light which is being working perfectly for me, and kept 2 automations that send notification at sunset and sunset +20 min to monitor the issue. They are both being triggered at 17h08 and 17h28 since Saturday. In comparison, Smart lights turned on my scene at 17h11 yesterday, which is the correct sunset time for my location.