This is using the segmentation tools within Target.
HI Jantzen - Andy is the developer on this, so to confirm it is the segmentation tools in Target itself. The ISP segment worked fine for us for several months but seemed to change sometime in late Oct or early Nov.
Can you clarify if you are using the segmentation tools within Target itself, or are you using the Audience core service of the Marketing Cloud to segment your visitors? If you're using the core service, are you creating the segment in Analytics as a historcal audience or in the Marketing Cloud as a real-time audiences?