Vue.js using a computed property to show or hide part of a component

I have a minimal reproduction in https://jsfiddle.net/3vkqLnxq/1/

It works as intended. The change is all b-* tags are changed to dom.

So the most possible cause is that b-form-select has some issue.

You should use getters and setters for computed property data binded.

Something like this:

computed: {
  issummit: {
    // getter
    get: function () {
      return this.name === '5a37fda9f13db4987411afd8';
    },
    // setter
    set: function (newValue) {
      this.systemname = newValue;
    }
  }
}

More:

https://v1.vuejs.org/guide/computed.html#Computed-Setter