Optional Enum shows nil in the debugger after parent is added to array

I have stuct x with an optional enum y:String, Codable. I do: var a = x() then a.myEnum = y.myEnumValue In debugger it will properly show a.myEnum to be y.myEnumValue But as soon as I do var b = [a] In debugger, the array shows correct values for any int or string I may have set but for the enum it shows nil. To make this more interesting when I examine b[0].myEnum in console I get the correct value: y.myEnumValue. Wondering if it is just an Xcode issue... link below is a screent shot of xcode (original link left off the actual issue. Below is the code fragment

import UIKit

enum x: String, Codable {
    case myEnumValue
}

struct y {
    var z: x?
}


class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        var a  = y()
        a.z = x.myEnumValue
        print((a.z)!)
        var j = [a]
        print((j[0].z)!)

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


}