Thread:Koopa422/@comment-1706203-20180706144033/@comment-24442815-20180706173356

I recall hearing something similar before. The scenes are supposed to be anime originals that expand upon things that the author didn't have time to include in the manga. Another example would be in the Forest Training Camp arc with the quirk training scenes. The author said  he didn't have time to include every character training with their quirk in a volume extra but he drew a brief outline of what they would have been doing https://bokunoheroacademia.wikia.com/wiki/File:Volume_9_Quirk_Training_1.png This page was later weaved into the anime.