After the update of 27-09-2021 in Asus TUF FX505DY, the Battery Health Charging feature in MyAsus automatically turns it to Maximum Capacity randomly. I haven't seen any specific pattern but yeah it has started to happen.
Armoury Crate UWP App 18.104.22.168
ROG Live Service 22.214.171.124
AURA Service (Lighting Service) 3.05.18
Armoury Crate service 4.2.10
Asus Framework Service 126.96.36.199