Assigning an Input Actions Asset that contains a custom InputProcessor or InputBindingComposite as "Project-wide Input Actions" throws errors upon play.
How can we reproduce it using the example you attached
Open the Scenes/SampleScene.unity and observe that everything works when pressing play.
(You can move the cube with the default movement controls and the custom RotateProcessor rotates input by 45 degrees.)
Select Settings/Controls.inputactions.
(This is the Input Action Asset generated by Unity with an additional RotateProcessor : InputProcessor added to the Move action.)
Click on "Assign as the Project-wide Input Actions" in the inspector.
(Alternatively, assigning it under Project Settings -> Input System Package as "Project-wide Actions" yields the same result.)
Press Play and notice the "No InputProcessor with name 'Rotate' (mentioned in 'Rotate') has been registered" errors in the console (with two distinct call stacks).
In the Editor, things are still working, but in an Android build, this leads to an immediate crash of the App.
Bug report sent.
What happened
Assigning an Input Actions Asset that contains a custom InputProcessor or InputBindingComposite as "Project-wide Input Actions" throws errors upon play.
How can we reproduce it using the example you attached
RotateProcessor : InputProcessor
added to the Move action.)