My HRM Pro was perfectly functioning until I updated fenix 6s pro to 19.10 from 15.20 few days ago: I updated the watch and went out for a run with the hrm and did an other run the next day, only then I realize that hrm pro was not functioning (cause the heart rate was taken by whrist sensor). First I tried to turn off and on the watch, took off and in batteries on hrm, reassociate watch and belt, nothing, then I changed batteries on the Hrm (but they had 7 month live they shouldn't have been discharged) and seemed working but the watch reported there was an update for the belt to 7.40 (was still on 7.1 but 7.40 is indicated as beta), so I updated to 7.40 and used it for some runs, in which garmin connect says HRM Pro was connected, cardio was detected (but i did'nt try to disconnect whirst sensor to be sure of it) but not the Running Dinamycs, sometime it disconnects, it says battery low (and it's new) and in rest the values are above 10/20 bpm the whrist sensor ones. I can't believe there was a malfunctioning at the same time of the updating, the two thing are related. My mistake was to updating when everything was ok...but these hrm are awful, it's the third broken (2 Run and a Pro) and too expensives for this quality.