I bought a new, sealed Vivoactive 3. I installed the app and put it to charge. After about an hour, it reached 100%, but when unplugged, it shuts down.
In the app, it appears offline after unplugging.
Now, if I put it back on charge, within 1-2 seconds, it tells me the battery is fully charged. However, if I unplug it, it turns off instantly.