Vue.js countdown timer doens't work

My problem is in showing the values ​​of the object. The table shows the tasks and the remaining time to finish. But it does not update the countdown timer ... The values ​​are in an Object in Task ID, for example: Object {1: "4017 D 13 H 2 M 49 S", 2: "0 D 0 H 0 M 0 S", ...} This object should always be updated to show the remaining time, but in the table where I show the object the same is only with the first value, without updating the timer.

<template>
    ...
     <table class="table" style="text-align: center">
      <thead>
       <tr>
        <th scope="col">...</th>
        <th scope="col">...</th>
        <th scope="col">...</th>
        <th scope="col">...</th>
        <th scope="col">Time Left</th>
       </tr>
      </thead>
      <tbody>
       <tr class="table-warning" v-for="task in tasks" :key="task.id">
        <th scope="row">{{task.id}}</th>
        <th>{{task.description}}</th>
        <th>{{task.created_at}}</th>
        <th>{{task.redline}}</th>
        <th>{{showLeft[task.id]}}</th>
     </tbody>
    </table>
    ...
    </template>

<script>
export default {
// variables declaration
  data() {
    return {
      user: [],
      tasks: [],
      numTasks: "",
      currentTime: [],
      showLeft: {}
    };
  },

  created() {
   // ProgressBar animation starts
    this.$Progress.start();
   // Get data from server
    axios.get("/user/name/data").then(response => {
      this.user = response.data;
      axios.get(`/user/missingTaskNum/data`).then(response => {
        this.numTasks = response.data;
        axios.get(`/user/missingTask/data`).then(response => {
          this.tasks = response.data;

          // Call function that will calculate time left
          this.updateCurrentTime();

         // ProgressBar animation stops
          this.$Progress.finish();
        });
      });
    });
  },

  mounted() {
   // start timer to refresh function every 1 sec
    this.interval = setInterval(() => {

      this.updateCurrentTime();

    }, 1000);
  },

  methods: {

    updateCurrentTime: function() {

      var now = new Date().getTime();

      for (let i = 0; i < this.tasks.length; i++) {

        this.currentTime[this.tasks[i].id] = new Date(this.tasks[i].redline) - now;

        if (this.currentTime[this.tasks[i].id] < 0) {

          this.$Progress.start();

          this.$Progress.finish();

          console.log("EXPIROU ID: " + this.tasks[i].id);

        } else {

          var days = Math.floor(
            this.currentTime[this.tasks[i].id] / (1000 * 60 * 60 * 24)
          );

          var hours = Math.floor(
            (this.currentTime[this.tasks[i].id] % (1000 * 60 * 60 * 24)) /
              (1000 * 60 * 60)
          );

          var minutes = Math.floor(
            (this.currentTime[this.tasks[i].id] % (1000 * 60 * 60)) /
              (1000 * 60)
          );

          var seconds = Math.floor(
            (this.currentTime[this.tasks[i].id] % (1000 * 60)) / 1000
          );

          this.showLeft[this.tasks[i].id] =
            days + " D " + hours + " H " + minutes + " M " + seconds + " S ";
        }
      }
      console.log(this.showLeft);
    }
  },

  beforeDestroy() {
    clearInterval(this.interval);
  }
};

</script>