Second FR165 - both not syncing about 1 in 10 activities

In June I bought a Garmin Forerunner 165. All fine until suddenly it would not upload some activities to Garmin Connect - say about 1 in 10. Everything else was synced, the step count, the body battery etc, they even showed the icons to show that I went for a run at 9am for example, but the run itself would not sync. I got fed up and returned the watch.

In September I decided to give it another go and bought another Garmin Forerunner 165. All had been going well and then today - same issue. My run will not upload, but it's visible as something I did in the body battery chart and the step count chart etc. Everything else is synced. 

What is going on? Why can this watch not consistently upload activities? Am I going to have to return this one too? 

  • Just to add - with the first 165, I could manually upload the runs by connecting the watch to my laptop. But I don't always have my laptop with me, so how can I get the watch to reliably sync with my phone, every activity, not just when it decides it wants to?

  • So I manually uploaded two missing activities via Garmin Express, everything was fine for a week, and today once again my run is not uploading but everything else is synced (steps, body battery, move IQ even knows I did a run but the run is not showing up). This is incredibly annoying. And obviously it's too late for me to return my watch now.