Possible mistake in Age of Ultron

So I just rewatched Age of Ultron and at the end right before Thor leaves he’s talking with Stark. He is talking about the infinity stones and says that they’ve had contact with 4 stones in the last few years. Space and Mind stones were in Avengers and the Reality stone in Thor Dark World but unless he’s counting the Mind stone twice because it shows up again in AoU that’s only 3. They haven’t had contact with the Soul, Time, or Power stones. Can someone confirm or deny this mistake?