Heart rate zones not accurate after workout

[PenguinUK]

My wife recently got a Charge 2 to better monitor her gym workouts alongside her flex 2 for swimming. Looking at the first few workouts she has done the heart rate monitoring is working on the workouts but on the excercise summary it is showing "peak" time when it should be "cardio".

By this I mean that the graph shows fat burn rates for 2 minutes and then cardio rates for 2 minutes with a flag showing her reaching a max HR of 166 (just in to peak) but none of the heart rate graph is actually red.

The problem is that the summary bar chart of "time in heart rate zone" shows 2 minutes peak and 2 minutes fat burn and 0 minutes cardio...

Any ideas why this this is happening and how to fix it?

[MarcoGFitbit]

Hello @PenguinUK, thanks for joining us, it's great to have you on board. 

This is indeed a very odd situation and in this particular case I would like to suggest restarting the Charge 2. Then, forceclose the app by double-tapping the home button on the phone and swiping up the app. 

If this situation is still repeating after performing this process, please reply to me with a screenshot of the heart reate graph and the exercise summary so I can check this further. 

I hope this can be helpful, give it a try and keep me posted.