Final update:
Called up Garmin Customer support this morning and had a long chat about the issues, they confirmed that it sounds like it's likely hardware, have opened a case with the team that specialised in issues with new devices, they're going to get back in the next 2-3 days with next steps: I guess some troubleshooting although I did include all the steps I took, including a full hard reset last night, and then hopefully a warranty replacement
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So I’m 3 runs into my lovely Forerunner 970, and noticing elevation issues on every run. I have calibrated the altimeter multiple times, and when I check during non activity it’s correct. But just after starting a run, Garmin thinks I’ve climbed 2500m in height in just a few hundred meters distance: not physically possible.
This is what my Garmin measured
Vs after I updated the activity to use the professional survey elevation data
This one is correct: 5k race that was pretty flat, just some very minor little inclines and declines
Watch is on the latest firmware 6.17.
Update:
