When you create a new group and then choose "Rename..." from the right click menu, the "(0/0)" will become part of the textbox. So, if you click somewhere else (thus canceling the renaming operation), the group name will be "New Group (0/0) (0/0)".
If you do this enough times you'll get a group name like "New Group (0/0)(0/0)(0/0)(0/0)(0/0)(0/0)(0/0)(0/0)", which is not very nice, although I think not many will rename groups so often
I'm using beta 2.7.0.49 on Mac OS 10.5.
Henrique Costa