Blogger login problems

Something has changed recently that I'm trying to narrow down. It's either Blogger/Google, Safari 5.0.5, or a plugin. When I click a Comments link on a Blogger-hosted blog entry, about 5% of the time the comments window reports problems logging into my Blogger account with the following error:

Your browser's cookie functionality is disabled. Please enable JavaScript and cookies in order to use Blogger.

If I close the Comments window and click the same Comments link again, it is able to login with my Blogger account and continue as it should. My pref for cookies is always set to "Only from sites I visit" and JavaScript is always turned on. Has anyone else seen this recently?