I just updated to 3.2.1 Multisite (sub-dirs) from WPMU 2.9. I use the WPMU LDAP plugin to auto-create new blogs and users automatically upon first successful login. Local user creation is disabled. I'm not sure that this issue is necessarily caused by the LDAP plugin however, as it seems to be a core default behaviour change in 3.2.
The default behaviour in my 2.9 install was that their blog would be automatically created and they would be taken to their new personal blog dashboard.
It seems with 3.2.1, these users are also being added automatically as Contributor to the main blog (blog id 1). The main blog is being set as their primary blog and they are taken to the Dashboard of the main blog, not their auto-created personal blog.
Does anyone have any insight into how I can prevent/change this behaviour? I don't want any new users auto-added to the main blog at all.