I have been using the fenix 5x for around 18 months mostly for running. I am using the stock firmware 10.0. This morning I started my run as normal, waited for the green circle indicating a fix and started my run. I noticed that I got a couple of km lap notifications at ridiculous times (i.e. 2 within the first 2 minutes). I continued my run and noticed that the watch had added a couple of kms to the actual distance I had run but it seemed to stop. After the run I looked at the map and something had clearly gone completely wrong. The start position was about 8kms from my actual starting position after which it jumps erratically for several minutes before seemingly getting a correct fix. I run this route regularly and start from my home. There are no high buildings or tree cover which might effect gps accuracy. It is like the watch thought it had a fix before it had one. I was using a garmin foot pod and tempe with a garmin running hrm strap.
Here is the garmin activity: https://connect.garmin.com/modern/activity/2994589817
Any ideas?
