Hi, there are two possibilities that I can think of:
1. Referrers from Site Y have been suppressed
Does the link on Site Y have a rel="noreferrer" attribute on the link? This is a web standard that prevents the referrer from being passed in the headers. This means the referrer will be empty, and there is no value available for Adobe to grab
2. The link from Site Y is actually being redirected when it lands on Site X, and the referrer is getting lost by the redirection logic
So, a lot of times, when developers code redirects, they don't think to maintain referrers (or the method they use doesn't support forwarding referrers (server side redirects can forward referrers, I don't think JS redirects can...).
A simple example is redirecting http to https, or redirecting a page with a missing / to the URL that has it.
Example:
- Site Y
- click on a link to Site X
- Site X (http://www.sitex.com/)
- This page has a referrer for Site Y, but requires https, and the redirect happens before the page loads and triggers any tracking
- Site X (https://www.sitex.com/)
- Referrers weren't forwarded, so this looks like direct traffic when the tracking triggers here on this page
You may need to check the HTML of the link on Site Y to look for the inclusion of noreferrer attributes, or check the network panel in your browser to see if the first page of Site X has something like a 301 or 302 redirect when coming from Site Y.
You can also check the headers of that first page on Site X to see is there a referrer available:
Use this code in your browser console:
document.referrer
If you have a referrer available, and it's still not included as a referrer in your tracking (you can check this in Adobe Cloud Debugger or Omnibug, or even look at the network panel for the tracking call), then there is probably something in your actual implementation suppressing it... and that is a whole new type of investigation (I know I have suppressed a few referrers in our payment and login flow, since I don't want to track the FB login app as a referrer source when people log into the site.. I want to maintain the referrer that brought them to the site that visit, not a mid-visit function that relies on an external service)