Analytics recording transaction under different AdWords campaigns
I'm managing an ecommerce website with conversion tracking enabled and linked AdWords and Analytics. Yesterday, I did a test by doing a google search for a keyword for which I have an AdWords campaign. In this case, I searched for 'iphone 5,' my ad appeared and I bought an iphone 5. But, an hour before this transaction I had clicked on one of my banner ads (different destination url) on the content network. Now, in Analytics, the conversion is recorded under the banner campaign and not under the search campaign. My question is, isn't the transaction attributed to the last ad campaign which led to the conversion? And two, which cookies take precedence in such a case?
Thank you for any one who helps!