After about 3 weeks of trying all kind of troubleshooting methods I managed to fix the calibration issue. Here is what I did.
In the past I have tried to reset the watch to factory defaults twice, but back then this didn’t fix the treadmill calibration issue. I have to admit that all my attempts to reset the watch were before, when the watch still had an older SW version.
Meanwhile I upgraded to the latest official SW version 3.10. But again this DID not fix my issue.
Then I tried things that other people advised me to do, like running with GPS, or adjusting the stride length manually (but apparently that is just for walking.
None of these methods worked. When I was about to put my watch on ebay, I said I will give it another try to do a last factory reset, and try the calibration once more.
After the factory reset I did not install any app or face from the IQ site, I didn’t change any settings in the watch, I left everything as the default
I ran then first time a 5k, and the watch recorded 7.6k (that was expected, because for the first time it never gets it right). The I calibrated and saved indicating that I ran 5k. At the next TM run, I ran also 5k, and amazingly the watch indicated this time the good distance, pace and speed. At the end of the race it showed 5.01k. This is very accurate.
So to wrap up, I don’t know why after my first resets the problem was not solved, but this time it was.
Another question that I have is why the watch ended up to behave like that with this calibration bug? Was this because of the few watch faces, apps, and widgets that I downloaded from the Connect IQ site? No idea.
In the end I will the watch. BTW Garmin support didn’t know how to fix the issue.
I hope this helps other people who have the same issue
