问当涉及节操作时，不调用performBatchUpdates完成处理程序。

EN

import UIKit
import CoreData

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    var window: UIWindow?
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        self.window = UIWindow(frame: UIScreen.main.bounds)
        
        let layout = UICollectionViewFlowLayout()
        layout.headerReferenceSize = CGSize(width: 30,height: 30)
        layout.sectionInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
        self.window?.rootViewController = UINavigationController.init(rootViewController: DashboardViewController(collectionViewLayout: layout) )
        self.window?.makeKeyAndVisible()
        return true
    }
}

class DashboardViewController: UICollectionViewController {
    
    let persistentContainer = PersistentContainer()
    
    lazy var resultsController: NSFetchedResultsController<Entity>? = {
        
        let fetchRequest = NSFetchRequest<Entity>(entityName: "Entity")
        fetchRequest.sortDescriptors = [NSSortDescriptor(key: "section", ascending: true), NSSortDescriptor(key: "name", ascending: false)]
        let resultsController = NSFetchedResultsController(fetchRequest: fetchRequest,
                                                           managedObjectContext: self.persistentContainer.viewContext,
                                                           sectionNameKeyPath: "section",
                                                           cacheName: nil)
        resultsController.delegate = self
        try! resultsController.performFetch()
        return resultsController
    }()
    
    private var itemOperations = [() -> Void]()
    private var sectionOperations = [() -> Void]()
    private var reloadRequired = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(add))
        self.collectionView.register(Cell.self, forCellWithReuseIdentifier: "Cell")
        self.collectionView.register(Header.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: "Header")
    }
    
    var itemIndex: Int = 0
    var section: Double = 0
    @objc func add() {
        let entity = Entity(context: self.persistentContainer.viewContext)
        entity.name = Int64(self.itemIndex)
        itemIndex += 1
        entity.section = Int64(floor(self.section))
        section += 0.5
        try! self.persistentContainer.viewContext.save()
    }
    
    override func numberOfSections(in collectionView: UICollectionView) -> Int { return resultsController!.sections?.count ?? 0 }
    
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { return self.resultsController!.sections![section].numberOfObjects }
    
    override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "Header", for: indexPath) as! Header
        let sectionInfo = self.resultsController!.sections?[indexPath.section]
        header.label.text = sectionInfo?.name
        return header
    }
    
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let item = self.resultsController?.object(at: indexPath)
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! Cell
        cell.label.text = String(describing: item?.name ?? -1)
        return cell
    }
    
    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let item = self.resultsController?.object(at: indexPath)
        item?.section = max(0, (item?.section ?? 0) - 1)
        item?.name = 10 + (item?.name ?? 0)
    }
}

@objc(Entity)
public class Entity: NSManagedObject {
    @NSManaged public var name: Int64
    @NSManaged public var section: Int64
}

class Cell: UICollectionViewCell {
    let label = UILabel()
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = .lightGray
        self.label.textAlignment = .center
        self.label.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        self.label.frame = self.contentView.bounds
        self.label.translatesAutoresizingMaskIntoConstraints = true
        self.contentView.addSubview(self.label)
    }
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
}
class Header: UICollectionReusableView {
    let label = UILabel()
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.backgroundColor = .gray
        self.label.textAlignment = .center
        self.label.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        self.label.frame = self.bounds
        self.label.translatesAutoresizingMaskIntoConstraints = true
        self.addSubview(self.label)
    }
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
}

class PersistentContainer: NSPersistentContainer {
    convenience init() {
        // create object model
        let nameProperty = NSAttributeDescription()
        nameProperty.name = "name"
        nameProperty.attributeType = .integer64AttributeType
        let sectionProperty = NSAttributeDescription()
        sectionProperty.name = "section"
        sectionProperty.attributeType = .integer64AttributeType
        let entity = NSEntityDescription()
        entity.name = "Entity"
        entity.managedObjectClassName = "Entity"
        entity.properties = [nameProperty, sectionProperty]
        let model = NSManagedObjectModel()
        model.entities.append(entity)
        
        // create container
        self.init(name: "Foo", managedObjectModel: model)
        let description = NSPersistentStoreDescription()
        description.type = NSInMemoryStoreType
        self.persistentStoreDescriptions = [description]
        self.loadPersistentStores(completionHandler: { (storeDescription, error) in
            if let error = error as NSError? {
                fatalError("Unresolved error \(error), \(error.userInfo)")
            }
        })
    }
}

extension DashboardViewController: NSFetchedResultsControllerDelegate {
    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
        
        reloadRequired = false
        if type == NSFetchedResultsChangeType.insert {
            print(">> insert")
            itemOperations.append { [weak self] in
                if let self = self {
                    self.collectionView!.insertItems(at: [newIndexPath!])
                }
            }
        }
        else if type == NSFetchedResultsChangeType.update {
            print(">> update")
            itemOperations.append { [weak self] in
                if let self = self, let indexPath = indexPath {
                    self.collectionView.reloadItems(at: [indexPath])
                }
            }
        }
        else if type == NSFetchedResultsChangeType.move {
            print(">> move")
            self.reloadRequired = true
            itemOperations.append { [weak self] in
                if let self = self, let newIndexPath = newIndexPath, let indexPath = indexPath {
                    self.collectionView.moveItem(at: indexPath, to: newIndexPath)
                }
            }
        }
        else if type == NSFetchedResultsChangeType.delete {
            print(">> delete")
            itemOperations.append { [weak self] in
                if let self = self {
                    self.collectionView!.deleteItems(at: [indexPath!])
                }
            }
        }
    }
    
    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange sectionInfo: NSFetchedResultsSectionInfo, atSectionIndex sectionIndex: Int, for type: NSFetchedResultsChangeType) {
        if type == NSFetchedResultsChangeType.insert {
            print(">> section insert")
            sectionOperations.append { [weak self] in
                if let self = self {
                    self.collectionView!.insertSections(IndexSet(integer: sectionIndex))
                }
            }
        }
        else if type == NSFetchedResultsChangeType.update {
            print(">> section update")
            sectionOperations.append { [weak self] in
                if let self = self {
                    self.collectionView!.reloadSections(IndexSet(integer: sectionIndex))
                }
            }
        }
        else if type == NSFetchedResultsChangeType.delete {
            print(">> section delete")
            sectionOperations.append { [weak self] in
                if let self = self {
                    self.collectionView!.deleteSections(IndexSet(integer: sectionIndex))
                }
            }
        }
    }
    
    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        
        collectionView.performBatchUpdates({ [weak self] () -> Void  in
            guard let self = self else { return }
            
            // execute single item operations first
            self.itemOperations.forEach { $0() }
            // execute section operations afterwards
            self.sectionOperations.forEach { $0() }
            self.itemOperations.removeAll(keepingCapacity: false)
            self.sectionOperations.removeAll(keepingCapacity: false)
        }, completion: { [weak self] (finished) -> Void in
            print("blockOperations completed")

            guard let self = self else { return }

            // in case of a move do a reload in case the item has also changed
            // it will not update otherwise
            if self.reloadRequired {
                self.collectionView.reloadData()
            }
        })
    }
}