With the new Input System I was trying to detect control scheme changes in Unity3d 2022.1.4f1* for a shared Action Map. It appeared that the C# events were being fired in batches when navigating on and off of unity. Turns out the fix was the PlayerInput Behavior was configured to "Broadcast Messages" instead of "Invoke C Sharp Events"

Broadcast Messages fires C# events in batches only when Unity Editor regains focus from alt tab. 

I was doing this to detect transitions between keyboard and gamepad controls to display different tutorials to prepare my game for the Steam Deck!