Okay, I solved the problem. Rather, there is an incompatibility with the new version of Lean Touch (Latest release date
Mar 4, 2022). In the FocusOnClick file I replaced the code

protected override void OnSelected()
    {
        print("OnSelect " + gameObject.name);
        if (follow)
            CameraEvents.OnRequestObjectFollow?.Invoke(gameObject, focusOnFollow);
        else
            CameraEvents.OnRequestObjectFocus?.Invoke(gameObject);
    }

with

protected override void OnSelected(LeanSelect select)
    {
        base.OnSelected(select);
        print("OnSelect " + gameObject.name);
        if (follow)
            CameraEvents.OnRequestObjectFollow?.Invoke(gameObject, focusOnFollow);
        else
            CameraEvents.OnRequestObjectFocus?.Invoke(gameObject);
    }

and respectively for the method OnDeselected