Android ActivityRecognition API, stops running in background

I'm dealing with the Activity Recognition API, trying to make it run in the background. So I've made a service that connects to Play Services and is alive all the time. I'm throwing a toast when the service is destroyed and created again. The problem is that after a while, even when the service is running, it stops detecting activities.

Here is some of the code from the service.

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Toast.makeText(this, "Service Started", Toast.LENGTH_LONG).show();
    buildGoogleClient();
    return START_STICKY;
}

private void buildGoogleClient()
{
    mGoogleApiClientActivityDetection = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(ActivityRecognition.API)
            .build();
    mGoogleApiClientActivityDetection.connect();

}

@Override
public void onConnected(Bundle bundle)
{
    if (mGoogleApiClientActivityDetection.isConnected() && detectionConnectionSet == false)
    {
        detectionConnectionSet = true;
        ActivityRecognition.ActivityRecognitionApi.requestActivityUpdates(
                mGoogleApiClientActivityDetection,
                Constants.ACTIVITY_DETECTION_INTERVAL_IN_MILLISECONDS,
                PendingIntent.getService(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT));
    }
}

I also override the onConnectionSuspended & onConnectionFailed where I reconnect if it not connected.

This code works fine for some time, then it suddenly just stops. Anyone have some ideas to why?

Thanks.

Turns out it was aggressive task management of some phone vendors.