My Series 6 went from lasting all day, to losing 1% per minute when undocked (this is how it felt, I didn't actually time it). It also wouldn't charge when docked, stuck at whatever percent it was at. If I undocked it and it lost a percent, and I docked it again, it would get stuck there. Doing a force restart allowed it to charge again to 100%. However, it was still losing 1% per minute when undocked.
I tried force restart (holding both buttons). Didn't work.
I deleted Moby Face from both watch and phone, then tried force restart again. Didn't work.
I also force restarted my phone. Didn't work.
I erased all content and settings from the apple watch, re-paired to phone, and restored from backup. Didn't work.
I gave up for 2 days and just left it charging the whole time, with it was stuck at 100% the whole time.
Today, I looked at it, and thought, let me force restart it again. Now, it appears to be working. It's been 1 hour and has lost 2% so far, which is normal for it (It's a series 6 at 83% health).
I have no idea what in this chain of things I did fixed it, or if it will stay fixed. It's only been an hour and I'm writing this post.
Based on what someone else said, they also had to erase and pair the watch, and then force restart it after to get it working again.
I didn't delete any other 3rd party apps, and I don't know if Moby Face was the actual culprit since deleting it didn't seem to do anything. But so many people are complaining about it, maybe it somehow weirdly played a part.
I would suggest trying the following based on no scientific reasoning:
- Delete the Moby Face App from both the watch and phone.
- Erase All Content and Settings form the Watch's reset menu.
- Pair to iPhone again and restore from backup.
- Force Restart the Apple Watch after it's done being set up.
Hope this helps. Sorry if it doesn't. Everyone seems to have such different solutions, making this issue difficult to troubleshoot.