Oh! I know what’s happening! The latest version of the plugin store the actionstream items as posts with a custom post type (taking advantage of a lot of the new features for that in WordPress). If you have a plugin installed that tweets all your blog posts and that plugin is poorly written so that it ignores post type, then it might mistakenly think each item is a new post! What plugin are you using? I can probably fix it for you and notify the plugin author of the bug.
@ 2011-186 17:16 UTC