Incorrect RectTransform width value when trying to read child RectTransform width.

     public RectTransform cellContainer;
     
     private int m_numCells;
     private float m_leftScrollLimit;
     private float m_rightScrollLimit;
     private List<RectTransform> m_cellRects;
     private HorizontalLayoutGroup m_horizontalLayoutGroup;
     
     void Awake()
         {
             m_cellRects = new List<RectTransform>();
             m_numCells = cellContainer.childCount;
             for(int i = 0; i < m_numCells; i++) {
                 RectTransform rect = (RectTransform)cellContainer.GetChild(i);
                 float w = rect.rect.width;
                 m_cellRects.Add((RectTransform)cellContainer.GetChild(i));
             }
             m_horizontalLayoutGroup = cellContainer.gameObject.GetComponent<HorizontalLayoutGroup>();
             Assert.AssertNotNull(m_horizontalLayoutGroup);
         }
     
         void Start() {
             float cellWidth = m_cellRects[0].rect.width;
             float canvasWidth = UIController.Instance.CanvasWidth;
             // Set the total width of the horizontal cell container
             float containerWidth = m_numCells * cellWidth + Mathf.Max(0, m_numCells - 1) * m_horizontalLayoutGroup.spacing + (UIController.Instance.CanvasWidth - cellWidth);
             cellContainer.sizeDelta = new Vector2(containerWidth, UIController.Instance.CanvasHeight);
             float leftAnchoredPosition = (containerWidth - UIController.Instance.CanvasWidth) * 0.5f;
             m_leftScrollLimit = leftAnchoredPosition + cellWidth * 0.5f;
             m_rightScrollLimit = -m_leftScrollLimit;
             ScrollToCurrent();
         }

I have the above script attached to a Scroll View. The cellContainer is the "Content" of the scroll view, which has a Horizontal Layout Group component. The content has child panels that can be scrolled horizontally. Each child panel has a Layout Element component and min width is set to 150. When I instantiate this UI gameobject for the first time the cellWidth in the Start function reads 150 correctly. But when I instantiate this UI screen later when needed, the cellWidth value is 0 and not 150 which makes the rest of the calculation wrong. I can't figure out why the first time the right value is reflected but not later. Do let me know if you have any idea about this. Thank you!