こういうコンポーネントを持つオブジェクトを、ストリーム発火前にDestoryするとUniRx内でInvalidOperationExceptionが発生するっぽい

gistfile1.cs

using UnityEngine;
using System.Collections;
using UniRx;
using UniRx.Triggers;

public class Test : MonoBehaviour
{
	void Start ()
	{
		var key = this.UpdateAsObservable()
			.Where(_ => Input.GetKeyDown(KeyCode.A))
			.First()
			.Subscribe(_ => Debug.Log("test"));
	}
}

試した環境
Unity 5.0.2f1
UniRx 4.8.2

例外発生時のスタックトレース

InvalidOperationException: sequence is empty
UniRx.Stubs.m__1B7 (System.Exception ex) (at Assets/UniRx/Scripts/Observer.cs:180)
UniRx.Observer+AnonymousObserver1[UniRx.Unit].OnError (System.Exception error) (at Assets/UniRx/Scripts/Observer.cs:71) UniRx.Observable+AnonymousObservable1+c__AnonStorey117[UniRx.Unit].<>m__1AD (System.Exception ex) (at Assets/UniRx/Scripts/Observable.Creation.cs:35)
UniRx.Observer+AnonymousObserver1[UniRx.Unit].OnError (System.Exception error) (at Assets/UniRx/Scripts/Observer.cs:71) UniRx.Observable+<FirstCore>c__AnonStoreyB71+c__AnonStoreyB81[UniRx.Unit].<>m__15D () (at Assets/UniRx/Scripts/Observable.Paging.cs:687) UniRx.Observer+AnonymousObserver1[UniRx.Unit].OnCompleted () (at Assets/UniRx/Scripts/Observer.cs:87)
UniRx.Observable+AnonymousObservable1+<Subscribe>c__AnonStorey117[UniRx.Unit].<>m__1AE () (at Assets/UniRx/Scripts/Observable.Creation.cs:35) UniRx.Observer+AnonymousObserver1[UniRx.Unit].OnCompleted () (at Assets/UniRx/Scripts/Observer.cs:87)
UniRx.Observer+AnonymousObserver1[UniRx.Unit].OnCompleted () (at Assets/UniRx/Scripts/Observer.cs:87) UniRx.Subject1[UniRx.Unit].OnCompleted () (at Assets/UniRx/Scripts/Subjects/Subject.cs:38)
UniRx.Triggers.ObservableUpdateTrigger.RaiseOnCompletedOnDestroy () (at Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableUpdateTrigger.cs:27)
UniRx.Triggers.ObservableTriggerBase.OnDestroy () (at Assets/UniRx/Scripts/UnityEngineBridge/Triggers/ObservableTriggerBase.cs:52)

破棄される際にOnCompleted()が呼ばれるところで例外発生してるっぽい。
First()をTake(1)にしたら解決したけど、このOnCompleted()時に例外にならないのは何故なんだろう。

First() は空のストリームではエラーだ、空かどうかが判明するのは OnComplete() のときだ。