Unfortunatlry for Jon, his second wish had more consequences than he thought. As he slept, the knowledge of his wish faded into dream, which faded into nothingness.
You see, he had wished no one would know he would have this power. He didn't exclude himself. He wouldn't even be able to piece together what he was doing.
And wishing on the stone would be pointless. Unless it was phrased perfectly, any wish to know what was going on would counter Jon's wish.
Jon was in for some interesting times.