Yuzu's character changed in the exact same way as Minami's did at the start of the series for mostly the same reason (forced to acknowledge their romantic feelings after being confronted with the possibility of their crush dating someone else) and before that they weren't at all thinking about the way they were behaving toward one another, Minami because she wasn't aware of her feelings and Yuzu because she was repressing them.
I think it was executed very poorly, doesn't mean I'm "deliberately missing a point" (what the hell does that even mean :P) It's similar only superficially - for one thing Yuzu actualy confessed before the manga even started, and we also got these (extremely) small glimmers that she still remembers even before the author felt the need to introduce the third character. But we're supposed to accept at face value that while all of this was going on, she was simultaneously completely oblivious like on that planetarium date (and all the other chapters really). That's not repressing feelings, that's just the author trying to pull a dumb plot twist (that everyone saw a mile away anyway), while the story suffered for it in the meantime. I don't think that whole progression was at all believable and that's why I didn't like it.
But anyway, I'll reiterate I'm glad we're past that point, story is already better for it.