Let's not speculate. There's nothing we can do even if we know anyway.
Knowing Mel it's should be an accident and not insidious intention. Like if she was messaging Coco and Rushia talking about her project in the year and that would count as leaking info to third party since they wasn't working there anymore. Or a retired manager. Or a dance teacher, ect... I can think of a million reason/excuse for her and that's would not be worth anything. Just remember the good time and move on.
