I seem to recall getting a non-master mode encore recently but I don't know for sure if I did.
Mostly I've just gotten encores on master-mode events lately, though, so it's been mostly master mode encores. It used to be that I would only get a master mode encore for a song that was in my event; usually Angela; Now that I've got 9 master mode songs unlocked it seems to be giving me one not in my event. I'm going to try and use that to my advantage by keeping the master mode events I'm better at out of the event.
Yesterday, I got a master mode encore for Take Me Out, and I didn't even remember ever mastering that one. I failed it miserably since I haven't played it in awhile. It is definitely being added to my event so that it *hopefully* won't come up as an encore.