tedster - 4:04 am on Sep 29, 2012 (gmt 0)

A link to an official communication from Google staff is fine - and this one comes from John Mueller, who was handson in SEO before he took the job at Google. He's been an excellent advocate for webmasters and a good communicator on the Google forums.

According to John, commenting on an explosion of 404 errors, it looks like this is the bottom line:

It does look like we're picking up something funny via JavaScript there. We're looking into what can be done in this particular case. In the meantime, keep in mind that 404 errors of URLs that are invalid...are not something that would affect your site's indexing or ranking...

This is a bit different from the opening post, however, because the server IS resolving the links rather than sending a 404 Not Found. While the source of those URLs may be the same JavaScript crawling problem, the fact the your server is resolving those URLs is something you should address. It increases your site's vulnerability to both accidental errors and malicious attacks.

I'd look into what kind of add-on characters can be appended to a valid URL and have the new URL actually resolve. Then take steps to either correct the bad configuration, or add a line in .htaccess to at least NOT return a 200 OK for those artificially padded URLs.