Mumei just wrapped her karaoke up. Near the end she talked a little about being gone and said she would be out for a while, with no date planned to come back. She didn't get into specifics about why, but she did slip in that it was not due/related to "civilization duties", which was surprising. I think most people thought she was taking a break to focus on school, especially since she started it at the end of the year time when many colleges are doing their finals.
edit: Switched over to IRyS's stream and she is chatting and talked about moving? Hadn't heard she is doing that, but awfully convenient timing that it is exactly the same time as Bae is moving to JP...