Never thought of it that way...This may be a winner~
She may have gotten some memories back but isn't sure if they're real so wants to talk to him about it. I'm sure the kiss would have to be some kinda plot device other than "lol lets set up a joke for next episode!"
If anything they'd have done the joke then and there. Instead the purposely dragged the discussion to the next episode to leave you hanging on why she was sad like that.