I have set up Ultratrack mode for GPS for my Hiling activity. When I record my 11.5km long hike it shows distance over 500km and second hike (cca 20km) shows distance almost 1000km. But when I check my trip on map then it seems to be OK. The path was not smooth and exact but the deviation (of recorded GPS path and real way) was max 20m. Any ide what is wrong?