How to properly turn off the Varia RTL 511

I am using the Varia 511 with Wahoo Elemnt and it works great. But, when I turn the Varia off by pushing the on/off button on the Varia, the red light turns off , but the blue light (small indicator light on the side) stays on - pulsing 2 times every 4-5 second and it never turns off. This is draining the battery. I don't have any other Garmin devices. How can I turn the Varia propely off, i.e. also turning the blue light off?