The CO2 sensor's internal light source flashes intermittently. In dark environments, this flashing LED may be visible through the fins of the air outlet grille. This is normal. 
The flashing light is only visible through the louvres at certain viewing angles.  Rotate the purifier slightly to change the viewing angle so that a louvre blocks the line of sight to the sensor.

You can find additional information about the Atem Series here: Guides and Manuals: Atem Series | IQAir

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