OnTriggerExit2D firing when the object stops.

Hi,

I have a problem with 2D colliders. I'm trying to learn Unity by making a simple tower defence game. Right now, I have a Turret tile with a CircleCollider2D marked as trigger and a Monster unit with a kinetic RigidBody2D and a PolygonCollider2D. I can move the monster with arrow keys from one tile to another. When I move in range of the turret, I recieve a OnTriggerEnter2D event and the turret starts firing at the monster. However, when the monster stops on a tile in range of the turret, I receive a OnTriggerExit2D event. Is this behavior excepected or am I doing something wrong? If so, Is there any way to get around this? Here is the relevant code:

 void OnTriggerEnter2D(Collider2D other)
     {
         if (other.gameObject.tag.Equals("Monster"))
         {
             inRange.Add(other.gameObject);
             particles.Play();
         }
     }
     void OnTriggerExit2D(Collider2D other)
     {
         if (other.gameObject.tag.Equals("Monster"))
         {
             inRange.Remove(other.gameObject);
         }
     }
 
 void Update() 
 {
         if (inRange.Count == 0)
         {
             particles.Stop();
             return;
         }
 .....................
         if (inRange.Count > 0 && !particles.emission.enabled)
         {
             particles.Play();
         }
 }
   

Thanks!