page with the ID "30" doesn't exist.
All Urls starting with an "?" don't have the right Statuscode 404 but 302.
wrong Url starting with "?" => 302 => Errorpage, but with the Statuscode 200.
I'm not alone, other WordPress blogs, i've tested, have the same bug. It's only importand, when a page is listed in the Searchengines and then I delete the Site or post in WordPress. The Searchengie doesn't get a 404 Statuscode, therefore the SE won't delete the page from the index.
Please try your Blog, and post your result. I don't find anything in the Support-Forum about this Bug.