title: [Vue warn]: Unknown custom element: <v-xxxxxx>
body: <p>I currently work on a static website built on Vuepress. I have an error that shows when registering a Vue component in a .md file. </p>
  
  <pre><code>[Vue warn]: Unknown custom element: &lt;v-b86f6654149c6&gt; - did you register the component correctly? For recursive components, make sure to provide the "name" option.
  
  found in
  
  ---&gt; &lt;Page&gt; at lib/default-theme/Page.vue
         &lt;Layout&gt; at lib/default-theme/Layout.vue
           &lt;Root
  </code></pre>
  
  <p>It fails to mount the component and the components tree in Vue devtools only displays </p>
  
  <pre><code>&lt;Page&gt;
       &lt;Content&gt;
  </code></pre>
  
  <p>with nothing inside. </p>
  
  <p>If I hit refresh though, the components are rendered correctly and I have what expected : </p>
  
  <pre><code>&lt;Page&gt;
       &lt;VXXXXXXX&gt;
           &lt;Component1&gt;
           &lt;Component2&gt;
  
  
  </code></pre>
  
  <p>Issue looks similar to what is referenced here : <a href="https://github.com/vuejs/vuepress/issues/1173" rel="nofollow noreferrer">https://github.com/vuejs/vuepress/issues/1173</a> but I could not find a working solution. </p>
  
  <p>For example, I have a <code>/docs/contact/README.md</code> that looks like: </p>
  
  <pre><code>---
  title: a title
  description: a description
  pageClass: homepage subpage contact
  headerText: Contact
  blackSubText: some text
  submitText: Envoyer
  submitImage: /img/icons/green-arrow.png
  
  ---
  
  &lt;headerTextComponent/&gt;
  
  &lt;formulaire type="contact" formId="/6db97999-f466-4250-aa47-bd6e96a6b520" :fields="['contactobject', 'message']"/&gt;
  
  
  &lt;blog/&gt;
  
  
  </code></pre>
  
  <p>and my above referenced custom components are in <code>/docs/.vuepress/components</code>, all being regular Vue components with a name property set.</p>