For those of you who have seen the first No Regrets OVA, you probably remember the soundtrack that played during Isabel's training montage, So Ist Es Immer:
After listening to the original AoT soundtrack, I've noticed that its "chorus" section is an acoustic, much more lighthearted lyrical version of the first section of vc-pf20130218, which played during Eren, Armin, Reiner and Bertholdt's night walk during the Trainees arc, as well as when Eren emerged from his Titan form in the Trost arc:
Skip to 1:05 for the first link and 0:50 for the second. Hear the similarities, or is it just me?