So is this what made Korone consider quit streaming?
It matches the timeline, her stream happend about a month ago, probably around the time coco announced to the other holomembers that she's planning to graduate.
Also if I remember correctly she stated that this had nothing to do with the health situation of her mother, I'm not 100% sure though.

https://www.youtube.com/watch?v=_nozZp5OQbI