Why won't my Apple Watch charge to 100% overnight?
My I watch will no longer charge to 100% when I leave it on the charger overnight. Is there a reason why this is happening?
[Re-Titled by Moderator]
Apple Watch Series 10
Question marked as
Did you check, if Optimized Charging and the Charging Limit is enabled?
You can disable this feature and charge your watch to 100% each time you put it on the charger.
Have a look at the related article, in which it is also being explained, why Apple introduced this option:
About Optimized Battery Charging on your Apple Watch - Apple Support