Occasionally you may see that your Max Heart Rate for a workout is higher than any of the values that register on the heart rate graph for that particular workout. This issue generally has a very simple fix.
There is a setting within the app called the GRAPH FILTER LEVEL, which is a setting that removes heart rate spikes and heart rate sensor noise from your workout graph. This filter can, however, also remove high and low heart rate readings from the workout graph that you may want to track.
In order to display those high and low heart rate values please open the app and tap MORE, then find the GRAPH FILTER LEVEL setting. Set this value to 0 (it is at 10 by default) and you should see all heart rate values tracked during your workout represented in the accompanying heart rate graph.