Hello,
I am having the same issue. It seems to be only affecting the Last Post Page. The homepage is fine, I am not using a Header Logo, but I am using a custom Header Image.
When you click on some of the “Post” pages, then it displays the Feature Image as the Header Image.
Here’s an example:
Bad Post Page: http://leoncegardenproject.com/2013/11/04/day-31-growing-with-the-sun/
Good Post Page: http://leoncegardenproject.com/2013/11/03/day-30-green-bean-flowers/
I’m curious if it’s because the Bad Post Page was my Last Post to my blog? I did a quick scan and found that all other Post Pages look fine.
I did the steps you outlined above, but that did not resolve the issue because I am not using the Header Logo.
I think there’s a bug in the code…