One of the devices in the Scene could have changed state, thus causing the Scene not to be set. That in turn will turn off the activator. Once it is off, as shown by the logs, SAR won't turn it off at 5 AM. Most likely the actual temperature of the bulb is not 2696. If it turns on and ends up at 2697, this would explain what you're seeing. Yes, turning the Scene on/off manually will work fine. But not for SAR, because if it sees the activator is off it won't turn it off.
Probably SAR should have a different option for activating a Scene instead of turning the activator on/off. A Scene activator is a special device type, and it is evidently not really going to work as you expect with SAR.
This will have to be addressed in the documentation. Attempting to turn off a Scene with SAR is not going to be reliable for the reasons above. Notice that the selector in Scene says "Which lights or switches do yo want to automate". That doesn't say Scene, and a Scene is not a light or switch.