[343] using el-data-picker with nuxt, but missing head config

sorry, this bug is so amazing, I don't know open issue at nuxt is whether proper, but I'm really need your help. I use element-ui to build a admin website, I use el-date-picker to select date because it's so easy and beautiful, but when I click this component at my page , the head that I configure at nuxt.config.js is missing. I crop some image to display this bug. before toggle after toggle, the global head config is missing. nuxt.config.js

 head: {
    title: 'starter',
    meta: [
      { charset: 'utf-8' },
      { 'http-equiv': 'X-UA-Compatible', content: 'IE=edge'},
      { name: 'viewport', content: 'width=device-width, initial-scale=1' },
      { hid: 'description', name: 'description', content: 'Nuxt.js project' }
    ],
    link: [
      { rel: 'icon', type: 'image/x-icon', href: '/favicon.ico' },
      { rel: 'stylesheet', href: '//cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css'},
      { rel: 'stylesheet', href: '//cdnjs.cloudflare.com/ajax/libs/toastr.js/latest/toastr.min.css'}
    ],
    script: [
      {src: '//cdn.bootcss.com/jquery/1.12.4/jquery.min.js'},
      {src: '//cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js'},
      {src: '//cdnjs.cloudflare.com/ajax/libs/toastr.js/latest/toastr.min.js'}
    ]
  },

so, why my head missing?