Understanding BigQuery datasource authentication

I’ve upgraded from v9.4 to latest version recently, and moved from doitintl bigquery datasource to the official one.

Now, my queries to BigQuery fail as unauthorized, and I see that although my datasource is configured to use the GCE Default service account, the requests made are using the K8s service account assigned to my pod, and not the VM’s default service account.

Is this expected behaviour? Thank you