You can unlock moona by starting over and not really interacting with the other ponies
Like 2 scenes or more with the other ponies.(It might be when you reach 2 that you are unable to get Moona's scene but I'm not fact checking it)
Go 5 days or so without getting too many scenes with the other ponies. (I think 2+ means you miss the scene)
Don't know how to fix it but it's like that for everyone on Android currently
