BETA UNLOCKED: New Media Manager!

@yaaraa
What happened to me just now is quite alarming.
I was working on a site of a client from her account. For a week or two now she has the new media manager in her account (she is not an expert, it just happened one day). When I wanted to upload a new image there was a message “welcome to your new media manager” (though it was there already) and after a few moments many files were uploaded to her manager - ALL FOLDERS OF ALL SITES I’VE MADE FOR THE LAST FIVE YEARS. This is now called “your site media” on an account that is NOT MINE. Yes, her site was once in my account and I’ve transferred it, but now it supposed to be a totally different account!
Are all my clients going to get all my media files as part of the new media manager?
This is SO wrong.
Please check this ASAP
Thanks
Tamara