This was an explicitly intended behavior change. When the user toggles "Auto-show Sidebar" on, it is an explicit signal by the user that they want the edge hover behavior. Thus we changed the behavior of the sidebar toggle button to show the overlay temporary sidebar if the user has selected "Auto-show Sidebar".
Previously, if the user had selected "Auto-show Sidebar", and they toggled the sidebar manually, it would remain there. In this open state, the edge hover would not work. This was confusing behavior because then "Auto-show Sidebar" became meaningless in that state, and users were confused why edge hover isn't working.
Now, if the user wants the old "sticky" sidebar behavior, they can simply turn "Auto-show Sidebar" off.