Sophia Lopez - S1-E4
Continuity mistake: During the scene where "Fluffer girl" is talking to Matt explaining she has the clap, in one camera angle Matt is seen next to her slowly stroking her back with his hand in a caring and concerned matter. Not even a split second later or two words further in her sentence, a different camera angle now shows Matt with his hands out in front of him on his lap.
Sophia Lopez - S1-E4
Continuity mistake: During the scene where Sean first meets Sophia Lopez in his office and he is about to counsel her, one camera view has Sean looking down at his notes and writing something, then looking up at Sophia as he begins speaking. A split second later, now from the opposite camera view, Sean looks up again and hasn't begun speaking yet.
Sophia Lopez - S1-E4
Continuity mistake: When Matt talks to the "fluffer", her lollipop disappears from her mouth in between shots. She then raises her arm and puts the lollipop back in her mouth. (00:20:35)
Sophia Lopez - S1-E4
Continuity mistake: When Christian talks to Matt outside the school, Matt hears the school bell ring and glances at the school and then back at Christian. In the next shot, he's facing the school and turns around to look at Christian again. (00:39:55)
Answer: "All I Know" by Art Garfunkel.