This is a feature the ICON2 lights use to preserve battery life when not in use.

The lights will go into a deep sleep after 15 minutes of inactivity and after the light enters this mode, it will cease all Bluetooth broadcasting. You can 'wake' the light by moving it or if it senses any movement i.e. vibration. The indicator LEDs light up after moving it if it has sat still for more than 15 minutes, This is in order to show the light is now awake.