Recharging my Ring Doorbell 2nd Generation

Just got an e-mail from my doorbell ( yeah, surprised me, too) that the battery was low, so I took it out of the holder and plugged it in with the charging cord that came with it. When I read the on line directions for recharging it says that I will see red and green flashing lights until it goes solid green to indicate it is fully charged. I do not get red and green lights, only blinking blue light. Is this normal?