Anything to progress the plot, huh? I kind of love it. The tease at the start, like a sensual fan dance "Ooh, you want this plot, don't you? Look, the protagonist remembers the plot, oh he's going to follow up on it any minute now..." and then FUCK NO! Here's a completely irrelevant side plot about two minor characters! Tune in next time, asshole, maybe there'll be some plot!
You gotta respect the author for pulling this shit on purpose like this. You can't tell me it wasn't. This is like tease and denial in manga form.