Penfold64 , via OnePlus 8 Pro , Sep 26, 2021 : After being connected to a Bluetooth device and having disconnected. The phone ring volume drops to muted. This does not happen every time but is frequent enough to be frustrating. The slider on the side of the phone is never moved, it remains on ring. Moving the slider to muted and back to ring has no effect. The only way to resolve is to manually change the ring volume. Please fix in the next update.