This is in spite of me running with a heart rate of 131-161bpm and swimming with a heart rate of 116-144bpm for extended periods. It had this problem in November and I contacted Garmin support and they talked me through how to fix it by enrolling in the Garmin Beta Software, but I am already enrolled in it since the last time it had this glitch.
I have already tried switching both my phone and watch on and off to no effect. Should I do a master reset?
Please advise! Many thanks in advance!