BigQuery Sync

I have a wierd situation. I am sending events from rudderstack to customer io, such as login, which is triggering identify call, and which is then creating a person within customer io. This event has email and id. However, the same event is being used to create a cohort in bigquery, which is then being sent to customer io every 30 mins. Now by the time its reaching customer io, there is already a person created with this email and id, since the login event is reaching the platform instantly (whereas bigquery - customer io sync happens every 30 mins). Hence I am getting this error last error: row id "5d24fdd0-bef9-4abf-8223-841eacd2294a": the email identifier is already associated with a different profile. What could be solution? 

My usecase: Send emails to people in the bigqueary cohort (e.g users who purchased products worth 1000 or more in the last month) when they come back to the site but don’t purchase.