[Edit: This all is in reference to the state of the nav widget in a symbol in the Editor. They are working fine in the rendered page.]
Current page highlight in the nav widget is only working for the home page - on the nav items for other pages, the "current" style formatting doesn't appear, as of about a week or so ago. When selecting those nav items (to check to be sure they were hooked up to the current page in the editor), the styling will sometimes flicker on for a moment, then off again. Haven't been able to pinpoint what triggers that flicker. (Edit - the nav widget in question is in a symbol, if that matters. Has worked fine previously as a symbol though.)
I've just created a couple of new pages in the site in question, and added new nav items for them, which seem to be working properly on the Current highlight state. Maybe this is an issue that got created at some point in time for certain individual nav items but is not endemic of the whole nav widget/symbol situation?
I will go back and try creating new nav items for the pages whose current nav items aren't highlighting.