Are you sure it was a favor quoin and not a time quoin? because there is one near Ilmenskie, you have to climb a little to catch it. It makes the learning go faster.
that's a favor quoin. hmm...well, you can SPEND favor points with certain giants in order to speed up learning, but unless you went to the shrine and clicked "spend favor points," it shouldn't have automatically started. prob'ly a bug of some sort.
I certainly didn't. In fact, I bet this has happened to me a few times; I've noticed I got fast learning without doing anything, but it could well have been the last few times I got a favor quoin.