The key sequence works for me as well now, but strangely what I also noticed earlier when the screenshot option reappeared in the power options menu, was that the "screen cast" option also appeared on the second page of the 'pull down' menu. I hadn't noticed that was missing before until I happened to swipe to the second page today and the UI made an animation to highlight the appearance of a new item and up it popped.
Any idea how this can be possible? Are these features periodically disabled by some service behind the scenes? Only change was running a SW update the night before.