NavigationController jumps back to RootView stutter under TabBarController

problem description

excuse me, the following picture shows the structure of my iOS application page, which basically uses TabBarController as the starting screen
, then the third sub-page (ThirdView) is NavigationController, followed by a FourthViewController (FourthView) under ThirdView

ThirdViewSegueFourthViewThirdView1

.

Please tell me where the problem is

< hr >

related codes

the following is the code for ThirdView to switch FourthView. There is nothing special, that is, Segue
FourthView returns to ThirdView and clicks the return button on the upper left

complete code Click this link to download

import UIKit

class ThirdViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Do any additional setup after loading the view.
    }
    
    @IBAction func buttonWasTapped(_ sender: Any) {
        performSegue(withIdentifier: "fourthSegue", sender: self)
    }
    
}
Feb.19,2022

this is a bug, of iOS12.1. You can refer to repair iOS12.1 UITabBar layout displacement bug this solution.

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