Question Sprites does not collide properly

Me following this instructions: World Interactions - Damage Zones and Enemies - Unity Learn, and it is my player-sprite script program.

Spoiler

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Idiotic_Ruby_Controller : MonoBehaviour
6. {
7.     public int maxHealth = 5;
8.    
9.     public float time_invincible = 2.0f;
10.  
11.     public float maxSpeed = 3.0f;
12.    
13.     public int health { get { return currentHealth; }}
14.  
15.     int currentHealth;
16.    
17.     bool is_invincible;
18.     float invincible_timer;
19.  
20.     Rigidbody2D rigidbody2d;
21.     float horizontal;
22.     float vertical;
23.  
24.     // Start is called before the first frame update
25.     void Start()
26.     {
27.         rigidbody2d = GetComponent<Rigidbody2D>();
28.         currentHealth = maxHealth;
29.     }
30.  
31.     // Update is called once per frame
32.     void Update()
33.     {
34.         horizontal = Input.GetAxis("Horizontal");
35.         vertical = Input.GetAxis("Vertical");
36.        
37.         if (is_invincible)
38.         {
39.             invincible_timer -= Time.deltaTime;
40.             if (invincible_timer < 0)
41.                 is_invincible = false;
42.         }
43.     }
44.  
45.     void FixedUpdate()
46.     {
47.         Vector2 position = rigidbody2d.position;
48.         position.x = position.x + maxSpeed*horizontal*Time.deltaTime;
49.         position.y = position.y + maxSpeed*vertical*Time.deltaTime;
50.        
51.         rigidbody2d.MovePosition(position);
52.     }
53.    
54.     public void ChangeHealth(int amount)
55.     {
56.         if (amount < 0)
57.         {
58.             if (is_invincible)
59.                 return;
60.  
61.             is_invincible = true;
62.             invincible_timer = time_invincible;
63.         }
64.             currentHealth = Mathf.Clamp(currentHealth + amount, 0, maxHealth);
65.             Debug.Log(currentHealth + "/" + maxHealth);
66.     }
67. }

And this is enemy sprite of which player should collide, script I mean.

Spoiler

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class EnemyController : MonoBehaviour
6. {
7.     public float speed;
8.     public float changeTime = 3.0f;
9.     public bool vertical;
10.    
11.     Rigidbody2D rigidbody2D;
12.     float timer;
13.     int direction = 1;
14.    
15.     // Start is called before the first frame update
16.     void Start()
17.     {
18.         rigidbody2D = GetComponent<Rigidbody2D>();
19.         timer = changeTime;
20.     }
21.    
22.     void Update()
23.     {
24.         timer -= Time.deltaTime;
25.        
26.         if (timer < 0)
27.         {
28.             direction = -direction;
29.             timer = changeTime;
30.         }
31.     }
32.    
33.     void FixedUpdate()
34.     {
35.         Vector2 position = rigidbody2D.position;
36.        
37.         if (vertical)
38.         {
39.             position.y = position.y + Time.deltaTime*speed*direction;
40.         }
41.         else
42.         {
43.             position.x = position.x + Time.deltaTime*speed*direction;
44.         }
45.        
46.         rigidbody2D.MovePosition(position);
47.  
48.     void OnCollisonEnter2D(Collision2D other)
49.     {
50.         Idiotic_Ruby_Controller player = other.gameObject.GetComponent<Idiotic_Ruby_Controller>();
51.        
52.         if (player != null)
53.         {
54.             player.ChangeHealth(-1);
55.         }
56.     }
57.        
58.     }
59. }

But in reality collisions almost no working. I have made two prefabs so called with enemies, with different speed and color each one. When I am trying to collide them in game mode, only the one of ten collisions is damaging Health of player, which is weird...



There should be text about damage, but no such things during 90% of collisions. What went wrong?