We have used custom event to send data to GA4 and we configured GA4 to BigQuery data link. We have found two problems:

-Events are shown with the same event_timestamp in spite of they have actually happened in user’s web browser in different time. For the example in the attached screenshot, sunmit_claims_starts and nbaDashboardInit have the same event timestamp, but they were fired in browser in different time.

-There are sessions that are not sending all the events from GA4 to BQ. for example user_logs_in_session has not been sent to BQ consisently.