This happened to me last night too. Yes I know the UI defaults to off now and resets on log in (sometimes), but even when turned on, and all addons turned off, still no bars or indicators. It kinda makes pvp a little difficult you know? I rode up to a group of EP a couple times last night like "Hey guys". Things ended bad both times...
The only fix I know of is to reboot the client until they come back. It too 4 or 5 times last night. This was a pts bug aswell. It took a patch to fix it.
@ZOS_GinaBruno @ZOS_JessicaFolsom please look at this quickly.