Venu 3s heart rate monitoring

I am finding issues with the heart rate monitor.  I did and ECG around 5:00 pm. The high heart rate was 139 with the average heart rate at 124.  When I update the app and check the heart rate data chart is shows the high heart rate for the day t9 be 112 and from 4:30-5:30 it shows the heart rate not going over 90.  I have a fib and monitor events but the app does not seem to register them.