If multiple campaigns are targetting the same location (mbox) it is possible to get an un-expected campaign/experience even when qualifying for the correct segment.
If you have configured two campaigns: Campaign A and Campaign B to target the same location (mbox1) they will be competing for the display. If the criteria for both Campaign A and Campaign B is being met. (IE: The visitor qualified for both targetted segments) the visitor will randomly enter Campaign A or Campaign B. Note: Once a campaign is entered the user will stay in it.
Use the highlight feature in the debugger to verify which campaigns are running on the page. Also run an mbox trace to verify which campaigns you are qualifying for. If there are multiple campaigns using the same location and you do not want his behaviour you will need to modify the locatoins (mboxes) being used for each of them. Otherwise this is working as designed.
This could also be because the Success Metric Advanced Options that are being used in the campaign. Success metric advanced options give you the ability to define custom behavior for both content viewing and counting when visiting a success metric.
The default behavior when visiting any normal success metric is to continue to show the user campaign content on the same experience and to never recount them.
To change the default content viewing or counting behavior on a success metric, you select the gear icon next to the success metric and modify the value in the drop down.