Environmental factors such as dense trees, steep hillsides, tall buildings, or even heavy cloud cover can impact or even interrupt the travel of the GPS signal between your watch and the satellites.
We recommend you search GPS before you start an activity and wait until GPS has full signal. The longer you wait the more it will grab and the better your signal will be.
If the issue still persists, please submit a feedback from the watch and Amazfit App and send us the Amazfit ID. Also please send us the screenshot of the activity including Details, Routes and Graphs to help us locate the issue.