Custom block not updating unless refresh

I have a custom block preview for a local video upload. It works fine, apart from when I add or delete the video the panel preview is not updated unless I save and do a page refresh. Not sure what I am missing?

index.js (of plugin)

panel.plugin("th/vid-block", {
  blocks: {
    vid: {
      computed: {
        vid() {
          return === 0
            ? false

      template: `
      <div class="w-full" @click="open">
        <video muted class="w-full ">
          <source :src="vid" type="video/mp4" />

fixed with v-if:

 <video  v-if="video"  muted class="w-full ">
          <source :src="video" type="video/mp4" />