I may be remembering wrong, but isnt the 2nd scene with Miruku right after you finish the first date with her? The one you do her on the shower
Raised her affection to 4* and had a perfect date, but nothing happened, I remember the mc overhearing her on the shower and then acts up on her, but this time he doesn't overhear her and nothing happens, I guess this is another bug? Unless I'm remembering wrong and the scene only happens later.