API错误？截至3月21日，v3 API中不再返回视频缩略图

Question

根据v3 API spec，在搜索中返回的视频应包含缩略图。

直到30分钟前，情况就是这样。

但是，现在，API正在返回JSON中没有“缩略图”属性的视频。

例如：

https://www.googleapis.com/youtube/v3/videos?part=snippet&key=(key)&id=Kq9z1gNjl0o

以前会回来：

{

    "kind": "youtube#videoListResponse",
    "etag": "\"idnvT0N6oxG_2o6LCWUdZsqtqtk/flm_N0PUouBHj2piDWTowbpXlNM\"",
    "items": [
        {
            "id": "Kq9z1gNjl0o",
            "kind": "youtube#video",
            "etag": "\"idnvT0N6oxG_2o6LCWUdZsqtqtk/9f5tPPIkXNmECTi095h9jBWV0s0\"",
            "snippet": {
                "publishedAt": "2010-06-27T00:07:30.000Z",
                "channelId": "UC3lizSW-J9kc8JR455mzv-w",
                "thumbnails": [
                   "small": {
                        "url": "http://ytimg.com/someimage.jpg"
                    }
                ]
                "title": "Kristen Bell - On Craig Ferguson - 4/19/08 - Wow",
                "description": "Interview",
                "channelTitle": "stewiefan33",
                "categoryId": "22"
            }
        }
    ]
}

现在返回：

{

    "kind": "youtube#videoListResponse",
    "etag": "\"idnvT0N6oxG_2o6LCWUdZsqtqtk/flm_N0PUouBHj2piDWTowbpXlNM\"",
    "items": [
        {
            "id": "Kq9z1gNjl0o",
            "kind": "youtube#video",
            "etag": "\"idnvT0N6oxG_2o6LCWUdZsqtqtk/9f5tPPIkXNmECTi095h9jBWV0s0\"",
            "snippet": {
                "publishedAt": "2010-06-27T00:07:30.000Z",
                "channelId": "UC3lizSW-J9kc8JR455mzv-w",
                "title": "Kristen Bell - On Craig Ferguson - 4/19/08 - Wow",
                "description": "Interview",
                "channelTitle": "stewiefan33",
                "categoryId": "22"
            }
        }
    ]
}

“缩略图”字段已消失，但仍在文档中。这是API中的错误吗？