If a sensor has been in its Aware State for more than 48 hours, Advanced Rules based on the Aware State will no longer trigger. The system assumes that a condition on which a sensor has been monitoring will have been acknowledged within 48 hours.
Resetting the Aware State
In order to resolve this, you will need to edit the Aware State configurations as per this article so that the current reading falls within the normal operating threshold. After the sensor accepts this configuration, you can edit the Aware State Threshold back to previous configurations, save, and once this has been done the sensor can again trigger Rules based on the Aware State.