Static variables not staying

I'm creating a script so a player knows when they collect 5 coins in a row. For some reason, if there is too much time between coin collection Unity resets my variable back to 0...and I'm not sure what is causing this.

 public class coin : MonoBehaviour {
 
     static int coinsCaughtInSequence = 0;
 
     void Start(){
 
         coinsCaughtInSequence = 0;
     }
         
     void OnTriggerEnter2D(Collider2D collider){
 
         if(collider.tag == "Player"){
 
             coinsCaughtInSequence++;
 
             if(coinsCaughtInSequence >= 5){
                 Debug.Log ("5 coins collected");
             }
 
             Debug.Log(coinsCaughtInSequence);
             Destroy(this.gameObject);
         }
     }
 }