GoPro Hero 4 Dual Charger flashing

So far i knew that the Dual Charger of GoPro turn his lights orange while charging and green when the job is done.
Today though it started flashing and i couldn`t figure out what is going on.
It doesn`t seem to make any huge trouble but still i would like to know what
it means.
Any coments,thoughts or information about this behavior is welcome.