title: Prop default gets overwritten in all mount-instances as soon as prop is passed once
body: <p>I have a <code>my-component.vue</code> which sets a <code>prop default</code> to <code>true</code>:</p>
  <pre><code>const props = defineProps({
      modelValue: String,
      editable: {
          type: Boolean,
          default: true
      }
  })
  </code></pre>
  <p>I'd assume now that whenever the component is imported and mounted, its <code>editable</code> prop is set to <code>true</code> if no no other value is passed as prop but as soon as I pass:</p>
  <pre><code>&lt;my-component :editable=&quot;false&quot;/&gt;
  </code></pre>
  <p>in any of the parent components, the <code>editable</code> prop inside <code>my-component</code> is permanently set to <code>false</code> in all instances of mounting it.</p>
  <p>Is that the desired behaviour of <code>default props</code> or am I doing something wrong?</p>