I had the same thoughts. He seemed rather absent, with his head in the clouds. Who knows, teenage problems...
We were outside because we preferred to stay in open air, and didn't make too much fuss about it so the manager didn't need to intervene (at least not visibly). We just gave him the wrong dish back and he came back with the right one after a while. How he fixed things in the back or what kind of a shaking he might've gotten there, I don't know. At least this thing he did right.