^My guess is intentionally. She probably just likes hearing Diana tell people they're married.
edit: Taking a look at the artist's tumblr is an absolute joy, there's so much Diakko there and it's all amazing.
I have never successfully pulled a blanket over a sleeping person without waking them. Not once in my life. I refuse to believe she was asleep for more than the first panel. (Especially since her hand moves in the panel with the kiss.)