Left Powerbeat pro shuts down with over 80% battery still remaining

My left powerbeat pro shuts down after about 30 minutes of use. When placed back in the charging case, it says it still has about 80% battery life. This issue is now occurring in the right piece as well, only after about an hour of use. The issue is resolved if I place them back in the carrier and reconnect them to the phone, which is very frustrating since I use them only for running. Could an Apple specialist provide a real solution that is not the typical canned response of resetting or updating iOS which I’ve already tried multiple times?