We're seeing about 3% of our traffic that marketing channels doesn't seem to be able to classify.
In trying to debug this, I set up a data feed where I can look at each individual hit... and it looks like on the visits that cause this problem, the page url and referrer have the same value (ie... I land on the search page, and the referrer is recorded as the search page as well). So the page URL is either overwriting the original referrer (but we're not using s.referrer), or there was no referring information in the first place, and the s_code is erroneously filling it in with the URL.
Has anybody seen this before? Any suggested solutions?
Well i believe what is happening to you is that analytics set the refer automatically from document.referrer; in your case you are facing a defect similar to this. read more about refer here. whenever this situation arises this results in a same origin or same uri as referrer in your pages to fix this you should use s.referrer in your website.