light flare flickering from particles

Hi there!

I am currently trying to create a particle system looking like an intense snow storm. I have a few static light flares in my scene which worked fine until i added a small script to move the particle system (emitting around 3000 snowflakes) with the player.

As long as the particle system is not moved, the light flares work fine. When i change the position or rotate the system, they flicker (about every 5 frames).

I really appreciate your help.

 using UnityEngine;
 using System.Collections;
 
 public class SnowPosition : MonoBehaviour {
 
     public Vector3 positionOffset;
     public float rotationY;
     public GameObject playerRoot;
 
     Vector3 setPosition;
     
     void Update () {
         setPosition = playerRoot.transform.position;
         setPosition += positionOffset;
 
         // if any of these next lines is included, it flickers
         transform.position = setPosition;
         transform.localEulerAngles = new Vector3(0.0f, rotationY, 0.0f);
     }
 }