Objects randomly drifting along x-axis away from y-axis

Question

I am trying to make just a simple slot machine game. Ideally, it would be just like the screen of a slot machine at a casino. The code probably isn't the cleanest so I apologize for that.

I would like the objects to move along the y-axis until they hit a y-boundary. After hitting this y-boundary they will return to the top which would be "SpawnPosY". For some reason, I can't figure out. The objects drift away along the x-axis from the y-axis (The objects to the right of the y-axis keep moving further right, vice versa) every time it hits this y-boundary.

I tried to fix this by adding another portion of code that moves the icon back to the position on the x-axis but they keep drifting (Yes, I've removed this line of code and no luck)

I tracked one of the Icon's movements across the X-axis just in case it helps to have data. 1 will represent its position from the start and every data point after that will be the x-axis position after one reel rotation (the icon hitting the y-boundary).

1. 0.369
2. -5.931
3. -18.533
4. -43.737
5. -94.145
6. -194.961
7. -396.593

Can anyone tell me why this is happening?

public class DestroyObjects : MonoBehaviour
{
    public GameObject[] iconPrefabs;
    public int iconNum = 0;
    public float SpawnPosY = 12f;
    private float SpawnPosX = 0.369f;
    public float yBoundary = -0.369f;

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        Vector2 spawnpos = new Vector2(transform.position.x, SpawnPosY);
        Vector2 fixXpos = new Vector2(SpawnPosX, SpawnPosY);

        if (transform.position.y < yBoundary)
        {
            transform.Translate(spawnpos);
            transfrom.Translate(fixXpos);
        }
    }
}

Answer 1

You might be better off using a different overload of the Translate function that takes individual x, y, and z values so that you can specify to only move on the y axis.

You should also apply Time.deltaTime any time you're moving to normalize the framerate

    var speed = 12f;
    transform.Translate(0, speed * Time.deltaTime, 0);

Also, move the creation of the spawn position outside of the Update so that it is only calculated once, not every frame

Unity documentation on transform.Translate