Although I still hope the two scenes are Amour related, I just thought of another scenario for the photo scene, which will be at the end of the episode, with the photo being taken about 3/4 of the way through. Serena is blushing because she's going to give the photo to Korrina at the end of her arc, as a memento of their journey, and then she quickly hides it when Korrina asks her what she has. I've noticed that she occasionally blushes when she is generous to someone.
Something between Korrina and Serena? One thing comes to mind, probably shouldn't say it. Maybe it's another love rival scenario, but one, Korrina seems like a dense character, and two, we don't need another, it'll just get repetitive.