The following scenarios are relevant:
What could be causing this?
A single-page visit (or session) occurs when a visitor leaves your website or mobile app from the landing page (or launch screen) without any further interaction. This results in a single event received in AudienceStream for that visitor. AudienceStream then performs additional processing on visitors at the end of a visit, but single-event visits are handled differently from multi-event visits.
A single-event visit/visitor meets all of the following conditions:
If any of these conditions are not met, the visit/visitor will not be treated as a single-event. In addition, if a single-event visitor returns for a new session, it will be treated as a new visitor in AudienceStream.
Single-event visits and visitors are not persisted in AudienceStream, are not passed to AudienceStore, and are not stored in AudienceDB.
Things to consider: