Factual error: Towards the end of the movie when Ally is in her hallway looking at Jack's old concert tour posters hanging on the wall, the poster closest to the camera says "Washington State Fair" and a 2011 date. Unfortunately, that fair did not get that name until 2013. Before that, it was called "The Puyallup Fair" (officially named the "Western Washington Fair"). Locals still call it "The Puyallup Fair" to this day.
Continuity mistake: The first time we see Jackson rehearsing, his brother comes to the first row to talk to him, always with his right arm down. There's a brief shot from a different angle where his arm is suddenly up. Then back to the previous angle where the arm is lowered for the rest of the scene.