For those wondering about the canon of when Azusa heard HTT for the first time, it's one of the places where anime canon and manga canon differ. In the anime, she was completely unfamiliar with HTT before her first day at Sakuragaoka High, and she didn't decide to join the keionbu until after seeing them play in the "Welcome New Students" event. In the original manga, she heard a recording of their first School Festival performance and decided to join the keionbu before stepping foot in Sakuragaoka for the first time (see Vol. 2, Ch. 1 of the original manga).
Now, something that I'm wondering is whether or not something that Azusa said in this chapter contradicts the previous manga canon. In this new Shuffle chapter, she said, "I heard a band at the Sakuragaoka High School Festival" (italics added for emphasis). By using the word "at", does she mean that she actually attended the show like Yukari and Kaede did, or does she still mean that she only heard a recording of it and I'm just reading too much into the translator's choice of words?