My b2evolution Version: 2.4.x

Hi
I've made a number of Blogs and connected different users with each blog. However there is a problem with some of the blogs. When a user connected with this blog - lets call it blog B - writes a post intended to be shown only in blog B it shows up only in main blog A. The user is placed in blog B when writing the post, and has rights to publish in this blog.
In other blogs this problem doesn't occur, though it looks as though both user and settings are the same as in the above mentioned!?