Also, by default, the FTP is set at 200W, so very low. If you have FTP detection on, your FTP have a very good chance of being much higher (maybe double?).
You could do a 30-20mn run as fast as you can, but at steady pace and that should get you the "real" value right away.
Maybe you're the lucky one? I had multiple bike and run sessions but never had an offer about changing power / hr threshold. Although it is set to automatically detect.
Whether or not it is normal depends on how much the numbers change.
My watch usually detects threshold during most runs on/above threshold intensity, this is normal and only proves that the auto detection works. The numbers (hr/pace/watts) however shouldn't change much from session to session as long as you do threshold sessions regularly.
If you only just started using the watch, I'd give it some time to collect more data and I'd expect the numbers to stabilize after a while.
A couple of reasons why it might not detect it for you:
- your max HR is set too high. If you have auto-detection for max HR turn it off (it never worked for me and proposed max that were way too high), and use 220-age. This is not perfect either, as it is a broad regression formula.
- you are not wearing an HR sensor that can detect the threshold. The wrist HR is not precise enough here, and some chest strap or arm bands don't send the HRV RR data. Use something like the Polar H9, H10 or HRM-Pro family.
- and the obvious: the effort is not intense enough for long enough. A good benchmark is a max, steady pace/power for ~10mn to be sure the detection would have an opportunity.
The first 2 possible reasons would explain as well why the built-in threshold test would not work as well, if you tried it.
