Conflict UI Display in system tabbar Liquid Glass Effect and custom tabbar with iOS 26 when using Xcode 26 build app

When using UITabBarController and set a custom tabbar: TabBarViewController.swift

import UIKit

class BaseViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

class HomeViewController: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .red
        navigationItem.title = "Home"
        tabBarItem = UITabBarItem(title: "Home", image: UIImage(systemName: "house"), tag: 0)
    }
}

class PhoneViewController: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .purple
        navigationItem.title = "Phone"
        tabBarItem = UITabBarItem(title: "Phone", image: UIImage(systemName: "phone"), tag: 1)
    }
}

class PhotoViewController: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .yellow
        navigationItem.title = "Photo"
        tabBarItem = UITabBarItem(title: "Photo", image: UIImage(systemName: "photo"), tag: 1)
    }
}

class SettingViewController: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .green
        navigationItem.title = "Setting"
        tabBarItem = UITabBarItem(title: "Setting", image: UIImage(systemName: "gear"), tag: 1)
    }
}

class TabBarViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let homeVC = HomeViewController()
        let homeNav = NavigationController(rootViewController: homeVC)
        
        let phoneVC = PhoneViewController()
        let phoneNav = NavigationController(rootViewController: phoneVC)
        
        let photoVC = PhotoViewController()
        let photoNav = NavigationController(rootViewController: photoVC)
        
        let settingVC = SettingViewController()
        let settingNav = NavigationController(rootViewController: settingVC)
        
        viewControllers = [homeNav]

        let dataSource = [
            CustomTabBar.TabBarModel(title: "Home", icon: UIImage(systemName: "house")),
            CustomTabBar.TabBarModel(title: "Phone", icon: UIImage(systemName: "phone")),
            CustomTabBar.TabBarModel(title: "Photo", icon: UIImage(systemName: "photo")),
            CustomTabBar.TabBarModel(title: "Setting", icon: UIImage(systemName: "gear"))
        ]
        let customTabBar = CustomTabBar(with: dataSource)
        
        setValue(customTabBar, forKey: "tabBar")
    }
}

CustomTabBar.swift:

import UIKit

class CustomTabBar: UITabBar {
    class TabBarModel {
        let title: String
        let icon: UIImage?
        
        init(title: String, icon: UIImage?) {
            self.title = title
            self.icon = icon
        }
    }
    
    class TabBarItemView: UIView {
        
        lazy var titleLabel: UILabel = {
            let titleLabel = UILabel()
            titleLabel.translatesAutoresizingMaskIntoConstraints = false
            titleLabel.font = .systemFont(ofSize: 14)
            titleLabel.textColor = .black
            titleLabel.textAlignment = .center
            return titleLabel
        }()
        
        lazy var iconView: UIImageView = {
            let iconView = UIImageView()
            iconView.translatesAutoresizingMaskIntoConstraints = false
            iconView.contentMode = .center
            return iconView
        }()
        
        private var model: TabBarModel
        
        init(model: TabBarModel) {
            self.model = model
            super.init(frame: .zero)
            
            setupSubViews()
        }
        
        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
        
        private func setupSubViews() {
            addSubview(iconView)
            iconView.topAnchor.constraint(equalTo: topAnchor).isActive = true
            iconView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
            iconView.widthAnchor.constraint(equalToConstant: 34).isActive = true
            iconView.heightAnchor.constraint(equalToConstant: 34).isActive = true
            iconView.image = model.icon
            
            addSubview(titleLabel)
            titleLabel.topAnchor.constraint(equalTo: iconView.bottomAnchor).isActive = true
            titleLabel.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
            titleLabel.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
            titleLabel.heightAnchor.constraint(equalToConstant: 16).isActive = true
            titleLabel.text = model.title
        }
    }
    
    private var dataSource: [TabBarModel]
    
    init(with dataSource: [TabBarModel]) {
        self.dataSource = dataSource
        super.init(frame: .zero)
        setupTabBars()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func sizeThatFits(_ size: CGSize) -> CGSize {
        var sizeThatFits = super.sizeThatFits(size)
        let safeAreaBottomHeight: CGFloat = safeAreaInsets.bottom
        sizeThatFits.height = 52 + safeAreaBottomHeight
        return sizeThatFits
    }
    
    private func setupTabBars() {
        backgroundColor = .orange
        
        let multiplier = 1.0 / Double(dataSource.count)
        var lastItemView: TabBarItemView?
        
        for model in dataSource {
            let tabBarItemView = TabBarItemView(model: model)
            addSubview(tabBarItemView)
            tabBarItemView.translatesAutoresizingMaskIntoConstraints = false
            tabBarItemView.topAnchor.constraint(equalTo: topAnchor).isActive = true
            tabBarItemView.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
            if let lastItemView = lastItemView {
                tabBarItemView.leadingAnchor.constraint(equalTo: lastItemView.trailingAnchor).isActive = true
            } else {
                tabBarItemView.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
            }
            tabBarItemView.widthAnchor.constraint(equalTo: widthAnchor, multiplier: multiplier).isActive = true
            
            lastItemView = tabBarItemView
        }
    }
}

UIKit show both custom tabbar and system tabbar:

the Xcode version is: Version 26.0 beta 2 (17A5241o) and the iOS version is: iOS 26 (23A5276f)