I have had the sports watch for about 3 years and it has always worked fine. Since the last watch update, 1.8.52, the gps data is all over the place. I can run a loop out and back and the gps track can be totally different on the return. The km marks are off which of course makes distance and speed incorrect. I update the watch to get the quick gps and I have also reset the watch but still the gps data is wrong
Here is a map of a run where ran out about 7km and back on the same track,the first 8km are wrong.