Hey guys, I got this charger some time ago, been working flawlessly, until today. It's currently flashing back & forth between red & green indicator while my Efest 18650 Red 1600 is on the charge, I've never noticed it doing this before & it has me concerned. Should I be worried, anyone experience it before? I also use this single battery charger to swap between my Efest 18650 Purple 2500.