Garmin Fenix/Epix Broadcast Heart Rate Issues

Hi All. Having issues with the broadcast heart rate feature on my Garmin Epix. For whatever reason, the heart rate is picked up through ZC as I start an activity but after 10-12 mins the Heart Rate drops off and the connection is lost for the remainder of the activity.
I know people will say the chest strap is the only way to go for accuracy but there are certain times where the chest strap is not at hand or starting a group ride in 1 minute and having the watch HR as backup if needed.