sectionInset not working with UICollectionView estimatedItemSize in iOS8 using AutoLayout

Question

I can't get my UICollection to properly set sectionInset.left margin when using self-sizing cells with estimatedItemSize. Cells of the UICollectionview should have a somewhat fixed cell height but dynamic width according to the text length.

Here is how it looks when the self-sizing is enabled:

And when the self-sizing is disabled:

Oddly enough, it seems that sectionInset.right is working, i.e. the margin is added on the right hand side of the UICollectionView.

Here's my custom UICollectionViewFlowLayout, i'm toggling self-size mode using the comment.

class myFlow: UICollectionViewFlowLayout {
    required init(coder: NSCoder) {
    super.init(coder: coder)

        self.minimumLineSpacing = 1
//        self.estimatedItemSize = CGSize(width: 100, height: 35)
        self.sectionInset.left = 20
    }

And my custom UICollectionView:

class myCV: UICollectionView {
    required init(coder decoder: NSCoder) {
        super.init(coder: decoder)

        self.layer.cornerRadius = 5.0
        self.layer.borderWidth = 1.0
        self.layer.borderColor = UIColor.lightGrayColor().CGColor

    }
}

I've laid out the label inside the UICollectionView cell using AutoLayout:

Answer 1

I've found a work around this - use contentInset property of UIScrollView, that is super class of UICollectionView. It is not strictly saying is answer, but, at least, a solution of the problem