macOS: Full Keyboard Access: Button click using Space not reliable after Backtab

Precondition: "Accessibility" -> "Keyboard" -> "Full Keyboard Access" is enabled

When navigating through the application to a button using Backtab, the button
is often not clickable using space.

See the following minimum working example. Navigate forwards and backwards using "Tab" and "Backtab" and use "Space" each time to click the button.

import QtQuick
import QtQuick.Controls
import QtQuick.Layouts

ApplicationWindow {
	id: root
	
	visible: true

	property string txt: ""
	
	ColumnLayout {
		
		Button {
			text: "A"
			onClicked: root.txt = "A"
		}
		
		Button {
			text: "B"
			onClicked: root.txt = "B"
		}
		
		Text {
			text: root.txt
		}
	}	
}

In some cases, clicking a button after using "Backtab" will not trigger the click event.
When the error occurs, the Focus-Indicator of macOS is on the correct button, but no click event is triggered.

In this situation you can do the following:

• Press "Tab" one time. The Focus-Indicator stays on the same element.
• Now, pressing space does trigger the correct click event.
• Pressing "Tab" another time moves the Focus-Indicator to the next element.

Or:

• Press "Tab" one time. The Focus-Indicator stays on the same element.
• Press "Tab" another time. Now, the Focus-Indicator moves to the next element.
• Press "Backtab". The Focus-Indicator moves to the previous element.
• Repeat: Pressing "Space" does not trigger the click event.