I recently set up authorship a couple days ago. I was glad it worked, I had an authorship image show up on my post in less than a week.
I ran a google site search for my domain today, and was surprised to find the homepage had my image, along with "by author".
It seems like I should have set authorship for domain.com/blog versus the root domain? I also had author archives disabled, which I believe routes the author link to the homepage. I enabled the archives, so I do have my author page back up.
When I check with Google's "Structured Data Testing Tool", the domain still get authorship. I changed my contribution link on Google+ to domain.com/blog as well, no luck.
Any help or suggestion please? I don't want to get penalized for this.