aria-selected not working with VoiceOver

In ChromeVox, this correctly reads "Prices, selected, 1/2" or "Features, selected, 2/2".

But in VoiceOver, this reads only "Prices, 1/2" (no 'selected' part).

Looks like a major bug in VoiceOver?

<div role="listbox">

<div tabindex=1 role="option" aria-selected="true">Prices</div>

<div tabindex=1 role="option" aria-selected="false">Features</div>

</div>