I have experiences a similar issue where when running the code using Xcode 16.0 / iOS 18, the app will crash. The trigger point is where instead of dequeueReusableCell, I pull from the previously saved "self.bannerItem" and the app crash with the follow error. *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'The collection view's data source returned a cell that is in the reuse queue. Cells must be retrieved by calling -dequeueConfiguredReusableCellWithRegistration:forIndexPath:item: or -dequeueReusableCellWithReuseIdentifier:forIndexPath:. Collection view: <UICollectionView: 0x107824200; frame = (0 59; 393 759); clipsToBounds = YES; gestureRecognizers = <NSArray: 0x600000c6eca0>; backgroundColor = <UIDynamicSystemColor: 0x600001767040; name = systemBackgroundColor>; layer = <CALayer: 0x600000248c60>; contentOffset: {0, 766.33333333333337}; contentSize: {393, 2340}; adjustedContentInset: {0, 0, 0, 0}; layout: <UICollectionViewFlowLayout: 0x10690c380>; dataSource: <AppTestiOS18.ViewController: 0x10690cd20>>; index path: (0-0); cell: <AppTestiOS18.ItemCollectionViewCell: 0x105707530; baseClass = UICollectionViewCell; frame = (46.6667 1740; 300 600); hidden = YES; layer = <CALayer: 0x60000024e6a0>>' The actual code can run using Xcode 15.4 and iOS 17 without any issues class ItemCollectionViewCell:UICollectionViewCell { static let cellIdentifier = "\(type(of: ItemCollectionViewCell.self))" } class ViewController: UIViewController { struct ContentCellItem { let height:CGFloat } enum ContentSection { case TopBanner(ContentCellItem) case FeatureBanner(ContentCellItem) case Title(ContentCellItem) case Webconent(ContentCellItem) case RelatedArticle(ContentCellItem) } let dataSrc:[ContentSection] = { var v:[ContentSection] = [] v.append(.TopBanner(.init(height: 200))) v.append(.FeatureBanner(.init(height: 300))) v.append(.Title(.init(height: 400))) v.append(.Webconent(.init(height: 800))) v.append(.RelatedArticle(.init(height: 600))) return v }() let collectionView:UICollectionView = { let t = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout()) t.register(ItemCollectionViewCell.classForCoder(), forCellWithReuseIdentifier: ItemCollectionViewCell.cellIdentifier) return t }() private var bannerItem:ItemCollectionViewCell! override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view. collectionView.translatesAutoresizingMaskIntoConstraints = false view.addSubview(collectionView) view.leadingAnchor.constraint(equalTo: collectionView.leadingAnchor).isActive = true view.trailingAnchor.constraint(equalTo: collectionView.trailingAnchor).isActive = true view.safeAreaLayoutGuide.topAnchor.constraint(equalTo: collectionView.topAnchor).isActive = true view.safeAreaLayoutGuide.bottomAnchor.constraint(equalTo: collectionView.bottomAnchor).isActive = true collectionView.layer.borderColor = UIColor.red.cgColor collectionView.layer.borderWidth = 3.0 collectionView.delegate = self collectionView.dataSource = self } } extension ViewController: UICollectionViewDataSource { func numberOfSections(in collectionView: UICollectionView) -> Int { return 1 } func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return dataSrc.count } func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { let section = dataSrc[indexPath.row] switch section { case .TopBanner(_): if self.bannerItem == nil { guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier:ItemCollectionViewCell.cellIdentifier , for: indexPath) as? ItemCollectionViewCell else { return UICollectionViewCell() } self.bannerItem = cell } self.bannerItem.layer.borderColor = UIColor.green.cgColor self.bannerItem.layer.borderWidth = 1.0 return bannerItem default: guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier:ItemCollectionViewCell.cellIdentifier , for: indexPath) as? ItemCollectionViewCell else { return UICollectionViewCell() } cell.layer.borderColor = UIColor.blue.cgColor cell.layer.borderWidth = 1.0 return cell } } } extension ViewController: UICollectionViewDelegateFlowLayout { func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { let cellWidth:CGFloat = 300 guard indexPath.row < dataSrc.count else { return CGSize(width: cellWidth, height: 1) } let section = dataSrc[indexPath.row] switch section { case .TopBanner(let item): return CGSize(width: cellWidth, height: item.height) case.FeatureBanner(let item): return CGSize(width: cellWidth, height: item.height) case .Title(let item): return CGSize(width: cellWidth, height: item.height) case .Webconent(let item): return CGSize(width: cellWidth, height: item.height) case .RelatedArticle(let item): return CGSize(width: cellWidth, height: item.height) } } }