In Safari a normal vue.js page produced an empty page every now and then for seemingly no reason. Since debugging with iOS is a pain in the ass and only possible through this hack, it took us a while to notice the console error telling us that the #app element was not found.
The index.html looked like this:
<body>
<script>
import('/js/module/bundle.js');
</script>
<div id="app">
</div>
</body>
But Safari wants it the other way around:
<body>
<div id="app">
</div>
<script>
import('/js/module/bundle.js');
</script>
</body>
And then it works.