C# IEnumerator is unchangable

i have a trouble with code below. What it does it builds a single line of road, one element after another.

currentLength = Random.Range(maxFloorLength - 2, maxFloorLength);
    List<GameObject> tempList = new List<GameObject>();

    for (int i = 0; i < currentLength; ++i)
    {
        foreach (GameObject g in pooledFloor)
        {
            if (!g.activeInHierarchy)
            {
                g.SetActive(true);
                g.transform.position = startPoint + buildDirection * i;
                g.transform.DOScaleY(5, 0.25f).Play();
                lastFloorPositions.Add(g.transform.position);
                tempList.Add(g);
                break;
            }
        }
        yield return new WaitForSeconds(0.05f);
    }

While this works as expected, when i change this to:

    currentLength = Random.Range(maxFloorLength - 2, maxFloorLength);
    List<GameObject> tempList = new List<GameObject>();

    for (int i = 0; i < currentLength; ++i)
    {
        foreach (GameObject g in pooledFloor)
        {
            if (!g.activeInHierarchy)
            {
                g.transform.position = startPoint + buildDirection * i;
                lastFloorPositions.Add(g.transform.position);
                tempList.Add(g);
                break;
            }
        }
    }

    foreach (GameObject g in tempList)
    {
        g.SetActive(true);
        g.transform.DOScaleY(5, 0.25f).Play();
        yield return new WaitForSeconds(0.05f);
    }

all it does is create ONE part of road (the one that should be at the end of tempList list). What i want is that script adds all the prefabs to list BEFORE doing something else with them, so i can add few thing in between. I tried to change it to void function, and calling some of this code as ienumerator, changing loop types etc. but nothing seems to work and i have no clue why is it not working. I checked with Debug.Log whether it still finds more than 1 prefab, and it does, but it only activates and scales ONE of them. I bet it's something obvious, but i just can't see it :/

How it looks:

How it should be looking:

Forgot to mention - its all inside of IEnumerator