I’ve just started working with the BigQuery export of GA4 data.

I’m trying to understand why the traffic fields (traffic_source.name, traffic_source.medium, traffic_source.source) are saying the session came from Paid Search, while the event level fields (campaign, medium, source) are saying it came from an Email campaign. Which is correct?

For example, for the below user the last 3 sessions record both Paid Search and an Email campaign against the same session. I would expect both to match when I look at the ‘session_start’ event.

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