audioClip数组元素为undefined

/////////////////////////////////////////////////////
import { _decorator, Component, Node, AudioClip, AudioSource, assert } from ‘cc’;
import { Constant } from ‘./Constant’;
const { ccclass, property } = _decorator;

interface IAudioMap {
[name: string]: AudioClip;
}

@ccclass(‘AudioManager’)
export class AudioManager extends Component {
@property([AudioClip])
public audioList: AudioClip[] = [];

private _dict: IAudioMap = {};
private _audioSource: AudioSource = null;
static _instance: AudioManager = null;

static get instance() {
    if (this._instance)
        return this._instance;
    this._instance = new AudioManager();
    return this._instance;
}

start() {
    for (let i = 0; i < this.audioList.length; i++) {
        const element = this.audioList[i];

        console.log(element.name);

        this._dict[element.name] = element;
    }  
    this._audioSource = this.getComponent(AudioSource);
    this.playBGM();
}

public playEffect(name: string) {
    const clip = this._dict['enemy'];

    console.log(clip);

    if (clip) {
        console.log('come in');
        this._audioSource.playOneShot(clip);
    }
}

public playBGM() {
    this._audioSource.play();
}

}

请问这个问题是必现的么?如果是偶现的,那么复现概率有多大?重启编辑器是否就会回复正常?