I just noticed this issue on my Ultra 2 in the last few days, it was almost like my watch would not fully charge while on the charger (even with optimized charging off), and then last night the battery drained from close to 100% down to 77% while sleeping. I'm not sure if it is from one of the beta upgrades or what, but I found a YouTube video that is somewhat of a general solution, but supposedly it has worked for some people complaining about the same thing. Link to the video: https://www.youtube.com/watch?v=Q1-Td6Su904 I might hold off on the beta upgrades on my Apple Watch until this gets situated, because that battery drain was frustrating!