[Unity] WaitForSecondsが正しく実行されない

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ItemGreen : MonoBehaviour
{
    private GameObject Player;

    public float effectseconds = 1.0f;
    public float JumpUpRate = 2.0f;
    private float baseJump;

    // Start is called before the first frame update
    void Start()
    {
        Player = GameObject.FindGameObjectWithTag("Player");
        baseJump = Player.GetComponent<NejikoController>().speedJump;
    }

    private void OnTriggerEnter(Collider other)
    {
        if (other.gameObject.tag == "Player")
        {
            baseJump = Player.GetComponent<NejikoController>().getJump();
            Player.GetComponent<NejikoController>().speedJump = baseJump * JumpUpRate;

            StartCoroutine(JumpDown());
            //Invoke("test", effectseconds);
        }

    }

    IEnumerator JumpDown()
    {
        Debug.Log("A");
        yield return new WaitForSeconds(effectseconds);
        Debug.Log("B");
        Player.GetComponent<NejikoController>().speedJump = baseJump;
        Debug.Log("C");
    }

    private void test()
    {
        Debug.Log("D");
        Player.GetComponent<NejikoController>().speedJump = baseJump;
        Debug.Log("E");
    }
}