As a temp work around have you tried to turn off "Optimized Charge Limit" under Settings>Battery>BatteryHealth.This is a pain. I have 2 45mm S7 watches, 1 Wi-Fi and 1 Cellular. The Wi-Fi version charges like normal, up to 80% and then to 100% before I use it for bed. My cellular only charges to 80% with the little hook going into the center. When I touch the screen, it asks if I want to fully charge or dismiss. Touching fully charge doesn't do anything.
Until this is resolved hopefully in Beta 2 this week or next, I spend my day with a 80% charge S7 45mm cellular and end the day with 30% or so.
I am not seeing this issue on my AWU.