Accelerometer event frequency slows down first 5 min using Angular Ionic on Android device

I am using

window.addEventListener('devicemotion', event => this.watchDeviceMotion(event))

watchDeviceMotion(event: any) {

  let motionData = {
    x: event.acceleration.x,
    y: event.acceleration.y,
    z: event.acceleration.z,
  }
  let rotationData = {
    alpha: event.rotationRate.alpha,
    beta: event.rotationRate.beta,
    gamma: event.rotationRate.gamma
  }

  if (this.getSensorData) {
    // console.log(JSON.stringify(motionData))
    // console.log(JSON.stringify(rotationData))
    this.userData.motionData.push(motionData)
    this.userData.rotationData.push(rotationData)
  }
}

to access accelerometer data on an Android device using Ionic with Angular. When inside the app, the event works at a frequency of 60 Hz but when the app is switched to background, the frequency drops around 9-10 Hz for the first 5 mins and at some point while still in background it goes back at 60 Hz and remains like that indefinitely.

I am also using the background plugin with

this.backgroundMode.enable();
this.backgroundMode.on('activate').subscribe(() => {
  this.backgroundMode.disableWebViewOptimizations();
});

I tried to add disableBatteryOptimizations() to the background plugin with the corresponding condition in config.xml but still no luck.

I also tried the plugins for Device Motion and Gyroscope but they behave the same.

How should I prevent the frequency from slowing down? Has anyone else encountered this problem before?

from Accelerometer event frequency slows down first 5 min using Angular Ionic on Android device