KyubuTest.cs

using System;
using UniRx;
using UnityEngine;

public class KyubuTest : MonoBehaviour
{
    public void Start()
    {
        var rp = new ReactiveProperty<int>(1);

        Observable.Timer(TimeSpan.FromSeconds(0.5)).Subscribe(_ => rp.Value = 2);
        Observable.Timer(TimeSpan.FromSeconds(1.0)).Subscribe(_ => rp.Value = 3);
        Observable.Timer(TimeSpan.FromSeconds(1.5)).Subscribe(_ => rp.Value = 4);
        Observable.Timer(TimeSpan.FromSeconds(2.0)).Subscribe(_ => rp.Value = 5);
        Observable.Timer(TimeSpan.FromSeconds(2.5)).Subscribe(_ => rp.Value = 6);

        // RaiseOnNextの変更を入れたらこうなる
        rp.Skip(2).First().Subscribe(x =>
        {
            Debug.Log($"v1 = {x}"); // 3
            rp.Skip(2).First().Subscribe(y =>
            {
                Debug.Log($"v2 = {y}"); // 5
                rp.Skip(2).First().Subscribe(x => Debug.Log($"v3 = {x}")); // こない
            });
        });

        // 現状
        rp.Skip(2).First().Subscribe(x =>
        {
            Debug.Log($"v1 = {x}"); // 3
            rp.Skip(2).First().Subscribe(y =>
            {
                Debug.Log($"v2 = {y}"); // 4
                rp.Skip(2).First().Subscribe(x => Debug.Log($"v3 = {x}")); // 5
            });
        });
    }
}