Invalid memory read unmarshaling parameters for patched empty method

[ShroudedNight]

What happened?

Modding Shadows of Doubt (latest experimental as of submission):
Attempting to patch the empty method [1] Actor.SelectedDebug(string, Actor.HumanDebug) yields invalid memory reads.

Yields the following profligacy of errors:
https://gist.github.com/ShroudedNight/34023da6a8145bbb5f35190cb2a38da9

[1] Game supplies a mono build for aiding in mod engineering. In that version, the method is empty.

Steps to reproduce

[BepInPlugin(MyPluginInfo.PLUGIN_GUID, MyPluginInfo.PLUGIN_NAME, MyPluginInfo.PLUGIN_VERSION)]
public class Plugin : BasePlugin
{
    private static PluginRuntime Runtime { get; set; }

    public override void Load()
    {
        try
        {
            Runtime = new PluginRuntime(Log);
            var harmony = new Harmony($"{MyPluginInfo.PLUGIN_GUID}");
            harmony.PatchAll();
        }
        catch (Exception e)
        {
            Log.FATAL($"Unable to load ${MyPluginInfo.PLUGIN_GUID}: {e}");
            throw;
        }
        Log.INFO($"Plugin {MyPluginInfo.PLUGIN_GUID} is loaded!");
    }

    [HarmonyPatch(typeof(Actor), nameof(Actor.SelectedDebug), [typeof(string), typeof(Actor.HumanDebug)])]
    public class Actor_SelectedDebug
    {
        public static bool Prefix(Actor __instance, string str, Actor.HumanDebug debug)
        {
            // Just a means of accessing the ManualLogSource
            Runtime.Log(LogLevel.Info, debug switch
            {
                Actor.HumanDebug.movement => $"Movement: {str}",
                Actor.HumanDebug.actions => $"Actions: {str}",
                Actor.HumanDebug.attacks => $"Attacks: {str}",
                Actor.HumanDebug.updates => $"Updates: {str}",
                Actor.HumanDebug.misc => $"Misc: {str}",
                Actor.HumanDebug.sight => $"Sight: {str}",
                _ => $"OutOfRange: {debug}"
            });
            return true;
        }

        public static void PostFix()
        {
            Runtime.Log(LogLevel.Info, "Actor.SelectedDebug(string, Actor.HumanDebug) => PostFix");
        }
    }

    [HarmonyPatch(typeof(Il2CppInterop.Runtime.IL2CPP), nameof(Il2CppInterop.Runtime.IL2CPP.Il2CppStringToManaged),
        [typeof(IntPtr)])]
    public class DebugStringConversion
    {
        public static unsafe bool Prefix(IntPtr il2CppString, ref string __result)
        {
            if (il2CppString == IntPtr.Zero)
            {
                __result = null;
                return false;
            }
            var length = IL2CPP.il2cpp_string_length(il2CppString);
            __result = length >= 0 ? new string(IL2CPP.il2cpp_string_chars(il2CppString), 0, length) : $"{il2CppString.ToInt64()}: {length}";
            return false;
        }
    }
}

BepInEx Distribution

3rd Party [Thunderstore]

Log outputs

Too long, See gist here: https://gist.github.com/ShroudedNight/34023da6a8145bbb5f35190cb2a38da9

Environment

- OS: Windows 10
- BepInEx: BepInExPack_IL2CPP v6.0.667 by BepInEx
- Game: Shadows of Doubt [latest experimental]