I found a few other errors when logged out as well, like when I searched for the above link, I got to a google search that had an amazon advertisement that linked to this url: http://goo.gl/xYWtGv That results in a redirect loop with the extension enabled in incognito mode.
If you are logged out of Amazon, a large number of things are broken on Amazon's website with this extension enabled. This is related to bug #7.
Reproduce:
I found a few other errors when logged out as well, like when I searched for the above link, I got to a google search that had an amazon advertisement that linked to this url: http://goo.gl/xYWtGv That results in a redirect loop with the extension enabled in incognito mode.