Can I ask for more clarification around your segment, how you are using it, and how you are verifying it?
Campaigns are generally using custom expiry.... such as Visit, or 1 Week, or 1 Month, etc....
Also, what metric are you using when you are verifying your segment? Is it possible your campaign was set on an action (s.tl) and IF you have the dimension set to "hit" instead of visit, when you pull a report by Page View, you may not see the hit, and without an attribution the value may not be brought forward into other hits in the dimension....
Or maybe you have a segment applied at the panel level that is causing some interference on how the data is showing....
The more you can share (even if you use pseudo examples to protect your real data) would help immensely.