Offers without affiliate ID in url?

Hi,

When checking some of the CPA links given to me by the networks, I've noticed that some of the offer pages that the links point to show my affiliate id in the url, but others don't, and show the same url no matter what number I put in the network tracking link. How are these offers tracking which affiliate the conversion came from? Could it be that they're simply cheating the affiliates?

They show it for a split second and it adds a cookie, and then redirects to the page without the aff link

So how's the link look for one url that dosent have your affiliate ID in it?
I guess you'r wrong.