Character is pushed off platform only when moving

I'v been trying to get my character to stick to a moving platform, great that works, but only if standing still otherwise the character is pushed off the platform very violently.

I'm using a simple trigger script to trigger the parenting of the player to the moving object, the trigger box collider is parented under the platform and the player is parented to the collider once triggered.

 #pragma strict
 
 function OnTriggerStay ( other : Collider ) 
 {
 if (other.tag == "Platform")
 { this.transform.parent = other.transform.parent; Debug.Log ("A", this); }
 }
 
 function OnTriggerExit ( other : Collider ) 
 {
 if (other.tag == "Platform")
 { this.transform.parent = null; Debug.Log ("B", this); }
 }