Why on Xcode 11, UICollectionViewCell changes size as soon as you scroll (I already set size in sizeForItem AtIndexPath:)?
I have the same problem. And my solution is to change the Estimate size to None in the Xcode 11.
You set collectionview Estimate size to None in Xcode 11. The reason for this is that cells in a UICollectionView can now self-size with Auto Layout constrained views in the canvas. To opt into the behavior for existing collection views, enable “Automatic” for the collection view’s estimated size, and “Automatic” for cell’s size from the Size inspector.
If deploying before iOS 13, you can activate self sizing collection view cells by calling performBatchUpdates(_:completion:) during viewDidLoad()
Ref:https://developer.apple.com/documentation/xcode_release_notes/xcode_11_release_notes
This problem is coming in Xcode 11. Go to the attribute inspector and change the estimateSize to None. will fix every thing.