I was also having a crash, in iOS 14 only, on a Self Sizing Collection View Cells when calling collectionView.moveItem(at: fromIndexPath, to: toIndexPath).
The workaround I've found is to switch estimatedItemSize to CGSize.zero just before and change it back to UICollectionViewFlowLayout.automaticSize after calling moveItem, like this:
layout.estimatedItemSize = CGSize.zero
collectionView.moveItem(at: fromIndexPath, to: toIndexPath)
layout.estimatedItemSize = UICollectionViewFlowLayout.automaticSize
This can cause a small glitch in the UI but at least it doesn't crash.
Hope this helps someone.
Topic:
UI Frameworks
SubTopic:
UIKit
Tags: