Have been using my RCT715 for several months now without an issue. But recently the device will not fully charge. No matter how long I leave it plugged in the green light remains flashing and never goes solid. When I check the charge level on my Garmin head unit to which it is paired the charge is never full. Firmware is up to date and I have tried several different leads and charging points. I cannot recall if this issue has happened since the last firmware update or not. Help please as it is very frustrating.