CATransform3D not being applied properly in custom UICollectionViewFlowLayout - ios6

Question

I'm having a strange issue with custom UICollectionViewFlowLayout, my cells contain an imageView, I apply a zoom effect to my cells... however I think that I'm doing something wrong with the Zoom Effect, it's strange, because my cells get scaled correctly, the problem is that the imageView for some cells is not.
Here's the relevant code (I think) for this issue, (note that If I remove the method: - (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect or the CATransform3DMakeScale, the problem doesn't seem to appear.)
///// UICollectionViewController.m
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
HICollectionViewCell *cell = (HICollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:COLLECTION_VIEW_CELL_ID forIndexPath:indexPath];
[self customizeCell:cell atIndexPath:indexPath];
return cell;
}
#pragma mark - CollectionView FlowDelegate
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return CGSizeMake(200.0f, 200.0f);
}
#pragma mark - "Private" Methods
- (void)customizeCell:(HICollectionViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
UIImageView *view = (UIImageView *)[cell.contentView viewWithTag:kCollectionViewCellSubViewTag_imgView];
if (!view.image) {
view.image = [UIImage imageNamed:#"placeholder.png"];
}
}
The Custom Layout Inherits from UICollectionViewFlowLayout
/////// CustomLayout.m
static const CGFloat ACTIVE_DISTANCE = 200.0f;
static const CGFloat ZOOM_FACTOR = 0.3f;
- (id)init
{
if(self = [super init]) {
self.itemSize = CGSizeMake(ITEM_SIZE, ITEM_SIZE);
self.scrollDirection = UICollectionViewScrollDirectionHorizontal;
self.sectionInset = UIEdgeInsetsMake(200.0f, 0.0f, 200.0f, 0.0f);
self.minimumLineSpacing = 50.0f;
}
return self;
}
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
return YES;
}
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSArray *attributes = [super layoutAttributesForElementsInRect:rect];
CGRect visibleRect;
visibleRect.origin = self.collectionView.contentOffset;
visibleRect.size = self.collectionView.bounds.size;
for (UICollectionViewLayoutAttributes *attribute in attributes) {
if (CGRectIntersectsRect(attribute.frame, rect)) {
CGFloat distance = CGRectGetMidX(visibleRect) - attribute.center.x;
CGFloat normalizedDistance = distance / ACTIVE_DISTANCE;
// Apply a zoom factor to cells within ACTIVE_DISTANCE
if (ABS(distance) < ACTIVE_DISTANCE) {
CGFloat zoom = 1.0f + ZOOM_FACTOR * (1.0f - ABS(normalizedDistance));
attribute.transform3D = CATransform3DMakeScale(zoom, zoom, 1.0);
attribute.zIndex = round(zoom);
}
}
}
return attributes;
}
As the FlowLayout appears everything looks fine.
Then I start to scroll and I notice that the background layer of the cells to the right starts to show off (backgroundColor is orange)
As you can see, after two cells, the third one ( that starts to appear, looks OK again ).
Maybe it's an issue with the cell queue and dequeue (and the imageView being re-used or something?).