It doesn't seem like none of you talked about it before, but on yesterday's stream Coco mentioned how the graduation was decided at least 3 months ago, and the other members knew for all this time against the staff's recommandation.
Kanata was, of course, the first to know.
This explain why she said she was supposed to be already graduated, since the decision was taken a long time ago.
One thing to note was the break taken a month ago, where in a tweet she said how she couldn't think of anything safe/idol-like to stream, confirming her explanation about "creative differences".
In one of her streams at the beginning of May kson also mentioned how her streaming activity would increase in the Summer, and her YouTube Membership started at the end of February., though she kept using exclusively Mildom until two weeks ago.
Three months ago it's also also when (I can't confirm this because I just read it, I actually don't remember it) Coco cried in a stream before deleting it and a week after that Kanata wrote
her letter to Coco as shown in
this video.
Yesterday's stream also broke all superchats records, being now in 1st place for her earning streams. With just yesterday's stream, she's good to go for months without working.
All the membership's money will still go to her even after the graduation, until monetization is removed.
She also talked about how some of the other members reacted to the graduation, like Matsuri asking her LINE like a creep and Marine started talking about the weather.
She denied the possibility of her joining management or going back to the Land of the Free - killing all rrats about it - and basically confirmed her intention of continuing to stay in the Vtubers world, explaining her new model shown on Mildom.
kson started streaming on Mildom before the chinks attacked, but her activities increased a little in March (see month - number of stream in the pic), so 3 months ago.
Does any of this matter? No.