Google Webmaster Tools seems to be generating a lot of fake errors. About a month ago they fixed the false 404 errors and now this month, they are reporting false HTTP errors. Here is a screen capture of the overview report from my Webmaster Tools login area for this site:
There are a dozen or so reports on this issue at Google Groups with others complaining about this issue. It worries webmasters to see this issue. For me, I just brushed it off, but I can see how it can really worry e-commerce sites and publishers.
JohnMu of Google has confirmed the issue, calling it just a reporting glitch that will be fixed shortly. He said:
This appears to be an issue in the reporting side of things in Webmaster Tools. As far as I know, the "General HTTP errors" should be gone soon :-). Thanks for bringing it to our attention, you guys are the greatest!!
True, the feedback in the groups is an invaluable tool for Google to improve and fix issues.
Forum discussion at Google Groups.