External LEDs on Here GNSS is not working properly

Hi all.
We are using Pixhawk2.1 with Cube and Here GNSS Module. During the startup of Pixhawk, sometime the external LEDs on the Here GNSS is not glowing (to show the boot sequence).
After two or three time power reset it is coming back.
I hope those LEDs are on I2C port.
Is anybody faced this problem???

Code stack is ArduCopter 3.5.3