FAQ: Why Does My Light Briefly Turn On at 100% Before Dimming to the Requested Brightness?
This is not caused by the blueprint or automation.
When Home Assistant sends a light.turn_on action with a brightness value, some lights or integrations may:
- Turn the light ON immediately.
- Restore the previous brightness level (or default to full brightness).
- Process the requested brightness value.
- Adjust the light to the requested brightness.
This can create a brief flash at a higher brightness level before settling at the requested brightness.
The behavior occurs because the light or integration is handling the ON command and brightness command separately, even though Home Assistant sends them together in a single action.
How to Check
Trigger the automation so the lights turn ON at a high brightness level (100%), then allow the automation to turn them OFF.
Next, enable Night Lights so the next trigger will turn the lights ON at a lower brightness level (20%).
When Night Lights triggers for the first time, you may notice the lights briefly change from 100% to 20%. Allow the lights to turn OFF again, then trigger Night Lights a second time.
If the lights now turn ON directly at 20%, this indicates that the light is restoring its previous brightness level when turning ON and then adjusting to the new brightness setting. The change may only last for a fraction of a second, but it can still be noticeable.
If the lights still briefly turn ON at 100% the second time, the device may be configured to always power on at 100% brightness before applying the requested brightness level.
This behavior is controlled by the light or its firmware and is not caused by the blueprint or automation.
Things to Try
There may be a way to reduce or eliminate this behavior, depending on your light and integration.
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Use the Transition option in Light Control if your light supports transitions. This can help smooth out brightness changes when the light turns ON.
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Use the Dim Before OFF Option in Light Control so the light always dims to a lower brightness level before turning OFF.
This option can be particularly effective if you performed the check above and found that the second Night Lights trigger turned the light ON directly at 20% brightness. In this case, the light is likely restoring its previous brightness level when turning ON. By dimming the light before it turns OFF, the lower brightness level is stored as the last known state, which may prevent the brief flash at a higher brightness level the next time the light turns ON.
Note: These options may not work with all lights, as some devices are designed to always turn ON at a default brightness level before applying the requested brightness setting.
Enjoy
Blacky 
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