Hey,
My dev guy managed to solved it. I've asked him to share how and he said:
The buddypress is displaying friend list using jquery so that when you type @ to mention anyone in your comment or post then it will display lists of friends in dropdown from this list.
We have deque the script for non logged in users
Hope this helps, it didn't involve changing buddypress core, this list won't be displayed for non logged in users anymore.
Anyway I'm disappointed with support here, I think with issues like that even when it's related to buddypress directly rather than rtmedia bug/error, figuring it out with your knowledge of buddypress probably doesn't take long and you could help your clients with little effort.