CSHARP

InvalidOperationException: Calling Scene Raisefrom assembly reloading callbacks are not supported.

//Delay the open scene method call.
private void OpenScene()
{
  EditorApplication.delayCall += OpenSceneDelay;
}

private void OpenSceneDelay()
{
  EditorApplication.delayCall -= OpenSceneDelay;
  EditorSceneManager.OpenScene(ScenePath, OpenSceneMode.Additive);
}