I have an Epix Gen 2 and Edge 530 and whenever I do a ride I wear a chest strap and remove my watch.
Connect web and app both show gaps in HR data on the HR graph widget during my rides, but it shows the actual ride/activity. I've confirmed that the ride records my HR data, but why wouldn't/isn't the graph for the total day's HR activity represent the HR data that was captured during the ride?
It does however show inline data when I do a run with the Epix.