When a sensor is either located far from a Cloud Connector or there are numerous obstacles in between that reduces signal strength, then the sensor will use extra power to make sure that data is sent reliably. This is called a Boost (high power usage) mode. Ideally, the sensors should not be in Boost mode for longer periods as it will affect battery life.
If the sensor reports in boost mode (boost icon) we recommend installing an additional Cloud Connector to ensure coverage.
Please also refer to the Installation guide for more information.