Ionic Local Notification not trigger and sometime trigger before time

Ionic Local Notification not trigger or come sometime and sometime trigger before time set time I am facing different scenario

  1. when schedule notification set for 5 mint and app in background. then sometime notification trigger before time randomly e.g(4 mint or sometime 4.5 mint)
  2. when schedule notification set for 5 mint and app in background. then sometime notification trigger.

below is my code

this.triggerDate = new Date(this.myDate.setSeconds(this.myDate.getSeconds() + 300));


this.localNotifications.schedule({
  id: 1,
  title: 'mylimit',
  text: 'Please provide eat enjoyment and guilt experience' + new Date(this.triggerDate),
  smallIcon: 'resources/icon.png',
  data: { "mydata": this.stateType, "createdTime": this.myDate },
  trigger: {at: new Date(this.triggerDate)},
});