Problem with trial render

When I using Trail render with another offscreen render like camera.render(), for water reflection. console says:

Adding renderer during rendering is not allowed. UnityEngine.Camera:Render() PlanarReflection:RenderReflectionFor(Camera, Camera) (at Assets/Standard Assets/Water (Pro Only)/Water4 /Sources/Scripts/PlanarReflection.cs:171) PlanarReflection:RenderHelpCameras(Camera) (at Assets/Standard Assets/Water (Pro Only)/Water4 /Sources/Scripts/PlanarReflection.cs:80) PlanarReflection:WaterTileBeingRendered(Transform, Camera) (at Assets/Standard Assets/Water (Pro Only)/Water4 /Sources/Scripts/PlanarReflection.cs:93) WaterTile:OnWillRenderObject() (at Assets/Standard Assets/Water (Pro Only)/Water4/Sources/Scripts/WaterTile.cs:41) m_SceneHandle !=kInvalidSceneHandle

I am using unity3.54~~~~~~

Is anyone knows the problem?