collectionView单元格未正确显示内容

Question

我正在构建过滤器功能，您可以在其中选择所需的用户以查看其报告。本节几乎完成了，但是有一个错误，当我快速上下滚动时，某些选定的单元格被取消选择，而某些未选定的单元格被选中。
UserCell类包含一个UIView，一个UILabel和一个UISwitch。如何修复该错误，以便当我上下滚动时，单元格保持其选择？

编辑：
这是一些屏幕截图。第一个是当我切换5时，第二个是当我向下滚动时（底部的18不是bug）。

import UIKit

    class BaseCell: UICollectionViewCell {
        override init(frame: CGRect) {
            super.init(frame: frame)
            setupViews()
        }
        func setupViews() {

        }

        required init?(coder aDecoder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
    }

    class UserCollectionView: BaseCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {

        let cellId = "userCellId"
        var users = [User]()

        lazy var collectionView: UICollectionView = {
            let layout = UICollectionViewFlowLayout()
            let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
            cv.backgroundColor = UIColor.white
            cv.alwaysBounceVertical = true
            cv.dataSource = self
            cv.delegate = self
            cv.translatesAutoresizingMaskIntoConstraints = false
            return cv
        }()

        override func setupViews() {
            super.setupViews()
            users = UserDefaults.standard.getUsers() != nil ? UserDefaults.standard.getUsers()! : [User]()
            self.addSubview(collectionView)
            setupCollectionView()
        }

        func setupCollectionView() {

            collectionView.register(UserCell.self, forCellWithReuseIdentifier: cellId)

            collectionView.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
            collectionView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
            collectionView.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
            collectionView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true
        }


        func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
            return users.count
        }

        func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath as IndexPath) as! UserCell
            cell.user = users[indexPath.item]
            return cell
        }

        func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
            return CGSize(width: self.frame.width, height: 40)
        }
    }