My son used my watch, Epix pro, for a bike ride when his watch was being repaired. After that the max HR and the zones moved up. I changed back my Max HR to what it should be and left the zones to be calculated as percentage of max HR. I made sure that the general and running zones were correct in the app and on the watch and yet after an intensive run I found that my time in zones was calculated on the basis of the max HR obtained from the interpolation of my son's and my HR max rates and not the values registered on the watch.
