I wonder if anyone else has noticed that Optimized Charge Limit is no longer working properly as of WatchOS 9.4? Optimized Charge Limit is explained in this Apple Document somewhere near the end: About Optimized Battery Charging on your Apple Watch, which explains:
“This feature learns from your daily usage to determine when to charge to an optimized limit and when to allow a full charge. Optimized Charge Limit is on by default when you set up your Apple Watch Ultra.”
When I first got my Ultra last October it behaved as described in the article. It charged overnight to 80% and by the end of the day it was still charged to around 50%; even when I was scuba diving with the Oceanic+ app.
Then I upgraded to WatchOS 9.4. After that the watch went on a battery discharge spree that lasted four days or so and during which I had to charge the watch twice a day. After that settled down I assumed that Optimized Charge Limit would resume. It did not. Now it charges to 100% every night even though by the end of the day I still have 60-70% battery charge remaining.
In other words, it is no longer learning from my daily usage.
I have tried to disable Optimize Charge Limit, restart the watch and enable it again, but that didn’t work.