Recently, owners of blogs supposedly not associated with custom domains have complained of this oddity also.
Why not at least
Blog not found
Sorry, the blog you were looking for does not exist. However, the name xxxxxxx is available to register!
If your BlogSpot blog, not now and never previously part of a custom domain, is showing this symptom, please comment here with the blog name. If you're suffering from this idiosyncrasy, silence won't get the problem fixed.
>> (Update 5/28): Blogger Support has suggested a possible (distant) connection between template corruption and observation of this symptom.
>> Forum thread links: bX-*00080
>> Copy this tag: bX-*00080