iOS添加到主屏幕后PWA图标不显示问题求助

我的应用已支持PWA，但图标并非始终显示。已查阅各类PWA论坛，未找到解决办法。

以下是index.html中关联Web App Manifest及图标的代码：

<link rel="manifest" href="webmanifest.json" /> 
<link rel="apple-touch-icon" href="assets/icons/CC_192x192.png" />

图标位于指定路径且可正常访问，Web App Manifest文件配置如下：

{
  "name": "Name",
  "short_name": "ShortName",
  "id": "/",
  "theme_color": "#000",
  "background_color": "#fff",
  "display": "standalone",
  "scope": "./",
  "start_url": "./",
  "icons": [
    {
      "src": "assets/icons/CC_192x192.svg",
      "type": "image/svg",
      "sizes": "192x192"
    },
    {
      "src": "assets/icons/CC_192x192.png",
      "type": "image/png",
      "sizes": "192x192"
    },
    {
      "src": "assets/icons/CC_512x512.svg",
      "type": "image/svg",
      "sizes": "512x512"
    },
    {
      "src": "assets/icons/CC_512x512.png",
      "type": "image/png",
      "sizes": "512x512"
    }
  ]
}

已查阅Chrome开发者文档、HTML5 Boilerplate相关讨论以及Apple官方的Web应用配置文档，恳请各位提供帮助。

内容的提问来源于stack exchange，提问作者Lilit Mazmanyan