唯一的解决方法是调用onYouTubeIframeAPIReady()。
为此，我加了一个条件：

function onYouTubeIframeAPIReady(init) {
   if (init === "init") {
       return;
   }
   // Init your YouTube Player here, after the condition.
}

// First call here : The minifier notices the method is used, so it won't delete it
onYouTubeIframeAPIReady("init");

// Later, YouTube API will call this method
// (YouTube doesn't pass any parameters, so the player will be initialized in this case)
// YouTube API : onYouTubeIframeAPIReady();