WP Upgrade Bug – upgrade alert stays after upgrade

I have a WP install with a Network setup (3 blogs). I’m trying to regularly maintain the code, so I upgraded from WP 3.3 to 3.3.1.

After calling the /wp-admin/upgrade.php on the main blog, which ran an upgrade script to do a “network upgrade” on all the blogs, it executes and says that all blogs have been upgraded. However when I got to each blog’s Dashboard, a message appears advising that I should upgrade the blog to 3.3.1

There is not .maintenance file that I can see.

Any hints or help? Thanks in advance.