Flashbacks of Sakurasou and "Kouhai-kun" and the various ways different fansub groups tried to translate it before they just said fuck it.
Is this one of those weird things that's changed over the past 10 years or so, like removing the last comma from "x, x, and x"?
If the translator/editor/typesetter (regardless of how many people that accounts for) go with something that sounds better and rolls off the tongue better than what's actually grammatically correct, and the character isn't a grammar whore, then who cares? Next thing you know, people are going to get on Shirou's case for ending a sentence with a preposition in the heat of battle.
Also, thanks for the chapter and for using Senpai.