second vc is smaller that the initial vc - swift

Question

I got this problem on iPad after update yesterday: if I load the second view controller, it appears smaller that the initial one (see photos below). Interesting, that is happening only since my update to the new iOS on iPad. There is no such problem on iPhone: the both VCs have there the same size.
Here is the code:
import UIKit
class StartVC: UIViewController, ButtonDelegate {
var width = CGFloat()
var height = CGFloat()
override func viewDidLoad() {
super.viewDidLoad()
width = view.frame.width
height = view.frame.height
setTestBtn()
view.backgroundColor = UIColor.purple
}
func setTestBtn(){
let a = Button(frame: CGRect(x: 0,y: 0, width: width*0.2, height: width*0.2))
a.center = CGPoint(x: width*0.5, y: height*0.5)
a.backgroundColor = .cyan
a.delegate = self
a.setLabel()
a.label.text = "Go to the MainVC"
view.addSubview(a)
}
func buttonClicked(sender: Button) {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "mainVC") as! MainVC
let transition = CATransition()
transition.duration = 2
transition.type = CATransitionType.push
transition.subtype = CATransitionSubtype.fromRight
view.window!.layer.add(transition, forKey: kCATransition)
vc.view.frame = view.bounds
self.present(vc, animated: true, completion: nil)
print("# ViewController func buttonClicked() OK!")
}
import UIKit
class MainVC: UIViewController, ButtonDelegate {
var width = CGFloat()
var height = CGFloat()
override func viewDidLoad() {
super.viewDidLoad()
width = view.frame.width
height = view.frame.height
setTestBtn()
view.backgroundColor = .red
}
func setTestBtn(){
let a = Button(frame: CGRect(x: 0,y: 0, width: width*0.2, height: width*0.2))
a.center = CGPoint(x: width*0.5, y: height*0.5)
a.backgroundColor = .orange
a.delegate = self
a.setLabel()
a.label.text = "Go to the StartVC"
view.addSubview(a)
}
func buttonClicked(sender: Button) {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "startVC") as! StartVC
let transition = CATransition()
transition.duration = 2
transition.type = CATransitionType.push
transition.subtype = CATransitionSubtype.fromRight
view.window!.layer.add(transition, forKey: kCATransition)
vc.view.frame = view.bounds
self.present(vc, animated: true, completion: nil)
print("# ViewController func buttonClicked() OK!")
}
}

Answer 1

Since the release of iOS 13, the modal presentation style of View Controllers is chosen automatically by the system by default.
If you wish to counter this effect, this can help you.
vc.modalPresentationStyle = .overFullScreen
self.present(vc, animated: true, completion: nil)
Hope this helps!