Replaced battery. Now turns off at 60% battery life.
My Apple Watch series 3 powers off at around 60% battery life left. And will not turn on unless I connect it to the charger.
It will turn on and claim it has around 60% battery but if I take it off the charger it will quickly die again.
If I let it charge to 100% it still dies relatively quickly.
I don’t think there is a 100% battery charge being drained when it dies.