ICollectionView cells are not being correctly reused

I want to use a UICollectionView to show a serie of images that the user can choose from the gallery. So I implemented a UICollectionViewDataSource, however in the GetCell method there is a problem when IOS tries to reuse the cell. I can load into the collection view the first two images, when I load the third one, the first cell's content gets blank, the same thing happens to the second cell when I create the fourth one and so on.

Here is my code for the DataSource:

public MyCollectionDataSource(List<string> items)
{
      this.items = items;
}

public override UICollectionViewCell GetCell (UICollectionView collectionView, NSIndexPath indexPath)
{
      var cell = (PhotoCell)collectionView.DequeueReusableCell (new NSString ("PhotoCell"), indexPath);
      cell.Image = UIImage.FromFile (items[indexPath.Row]);
      return cell;
}

public override int NumberOfSections (UICollectionView collectionView)
{
      return 1;
}

public override int GetItemsCount (UICollectionView collectionView, int section)
{
      return items.Count;
}

I also Implemented UICollectionViewFlowLayout to give a linear layout to my collection view (I took this code from docs.xamarin.com/guides/ios/user_interface/introduction_to_collection_views/). This is how that looks:

public override UICollectionViewLayoutAttributes[] LayoutAttributesForElementsInRect (RectangleF rect)
        {
            var array = base.LayoutAttributesForElementsInRect (rect);
            var visibleRect = new RectangleF (CollectionView.ContentOffset, CollectionView.Bounds.Size);
            foreach (var attributes in array) {
                if (attributes.Frame.IntersectsWith (rect)) {
                    float distance = visibleRect.GetMidX () - attributes.Center.X;
                    float normalizedDistance = distance / ACTIVE_DISTANCE;
                    if (Math.Abs (distance) < ACTIVE_DISTANCE) {
                        float zoom = 1 + ZOOM_FACTOR * (1 - Math.Abs (normalizedDistance));
                        attributes.Transform3D = CATransform3D.MakeScale (zoom, zoom, 1.0f);
                        attributes.ZIndex = 1;
                    }
                }
            }
            return array;
        }

And here is the code which adds a new string path to the data source list of items:

galleryPicker.TouchUpInside += async (sender, e) => {
                var file = await picker.PickPhotoAsync();
                items.Add(file.Path);
                dataSource.items = items;
                InvokeOnMainThread(() => {
                    photoCollection.ReloadData();
                });
            };

I'm open to suggestions!! Attached are 2 images which show whats happening, the first one is when I have only 2 cells created, the second one happens when I create a third cell!