aria-selected scrollable Listbox Example does not follow best practice

[Row]

The unselected values/options should have aria-selected="false"

https://www.w3.org/WAI/ARIA/apg/patterns/listbox/examples/listbox-scrollable/

According
https://w3c.github.io/aria/#aria-selected

Value	Description
false	The selectable element is not selected.
true	The selectable element is selected.
undefined	The element is not selectable.

[JAWS-test]

According to https://w3c.github.io/aria/#aria-selected and https://w3c.github.io/aria/#option it is not necessary

The option, tab, and treeitem roles permit user agents to provide an implicit value for aria-selected when specified conditions are met.

If a user agent provides an implicit aria-selected value for an option, the value SHOULD be true if the option has DOM focus or the listbox has DOM focus and the option is referenced by aria-activedescendant. Otherwise, if a user agent provides an implicit aria-selected value for an option, the value SHOULD be false

[JAWS-test]

I agree with you that it is not best practice to omit aria-selected, see w3c/aria#1094