Self-sizing CollectionView/Cell

self-sizing-collectionview-cell.swift

// setup your collectionView
private let collectionView: UICollectionView = {
    let layout = UICollectionViewFlowLayout()
    layout.scrollDirection = .horizontal
    layout.minimumInteritemSpacing = 20.0
    layout.minimumLineSpacing = 20.0
    // important!
    layout.itemSize = UICollectionViewFlowLayout.automaticSize
    // change estimatedItemSize for a vertical example
    layout.estimatedItemSize = CGSize(width: UIScreen.main.bounds.width, height: 40.0)

    // collectionView
    let view = UICollectionView(frame: CGRect.zero, collectionViewLayout: layout)
    view.translatesAutoresizingMaskIntoConstraints = false
    view.contentInset = UIEdgeInsets.zero
    view.decelerationRate = .fast
    return view
}()

// you just need the basic stuff 
//MARK: - CollectionView -
extension YourViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    func collectionView(
        _ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        
        return dataSource.count
    }
    
    func collectionView(
        _ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        
        let data = dataSource[indexPath.row]
        return configureItemCell(indexPath: indexPath, data: data)
    }
}

/**
CollectionViewCell
*/
final class ItemCell: UICollectionViewCell {
    override init(frame: CGRect) {
        super.init(frame: frame)
        layout()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
        layoutIfNeeded()
        let size = systemLayoutSizeFitting(layoutAttributes.size)
        let frame = CGRect(origin: layoutAttributes.frame.origin, size: CGSize(width: size.width, height: size.height))
        layoutAttributes.frame = frame
        return layoutAttributes
    }
}

what is this layout() in override init(frame: CGRect) { method ?

Hi Antonio!
Code is perfect for sample cells without headers.
But I have a strange bug on iPhone 6S (iOS 15.8), headers overlapping:
when the user clicks on the first header, the second header does not move down after the last cell of the first header.
Have you met this bug before?
P.S.
This bug appears on iPhone 6S (iOS 15.8) only