Having used the 5X for a week i am generally happy with its performance and accuracy. However when running the watch seems to display an inaccurate reading of grade (most of the time the value is zero or sometimes just 1-2 regardless of the steepness of the hill). Altimeter reads fine. My previous Fenix 2 was displaying a realistic value when running up/downhill. Has anyone else noticed this? Is there a fix ?