I work for an online education company. We have multiple websites, most of which are hostnames of the same domain. The main exception is the site where parents go to enroll their children. This is a secure site built on the Salesforce platform with a different domain (force.com).
We use the Adobe Marketing Cloud Visitor ID Service on all websites (implemented using DTM) and use a combined ReportSuite in addition to individual ones.
I'm seeing a high percentage of "Internal" First-Touch Channel and Original Entry Page associated with the enrollment site (Combined RS).
I shouldn't even be seeing First-Touch Channel "Internal"; the "first-touch" should be the one associated with the entry website!
Looking at data feeds I can see many first visits starting on the enrollment site with one of the other sites as the referrer.
It seems to me that:
1) Cookies are being reset when visitors visit the enrollment site from one of the others
2) Third-party cookies are disabled preventing the demdex cookie from being set resulting in a new first-party cookie.
This is a serious problem because 30%-40% of enrollments are being attributed to a non-channel instead of the correct paid channel.
I normally call them but for the past few months you can no longer speak with somebody technical who may know what you're talking about. Instead you get a ticket writer who opens a ticket and maybe a tech will call you back at 9:00 PM!