I am experiencing issues with my Forerunner 645 Music locating and maintaining a GPS signal. It's always been quick to pick up GPS and tracks accurately during an activity. However, it has suddenly started taking between 5 and 10 minutes to establish a signal, and then loses the signal during an activity resulting in a straight line between points. I am using GPS+GLONASS and running software version 7.10(271a84f). I'm in Wiltshire, United Kingdom. Does anyone know if there is an issue with GPS or GLONASS, or is it a Garmin Device issue?