Client VPN Connection Logging Not Showing Federated Username

I have setup AWS Client VPN using AWS SSO as an IdP and in the connection logs I am not seeing the username. I see the following. How do we get the username to populate from a federated login?

{
"connection-log-type": "connection-attempt",
"connection-attempt-status": "successful",
"connection-attempt-failure-reason": "NA",
"connection-id": "cvpn-connection-xxxxxxxxxxxx",
"client-vpn-endpoint-id": "cvpn-endpoint-xxxxxxxxxxxx",
"transport-protocol": "udp",
"connection-start-time": "2021-03-29 15:27:31",
"connection-last-update-time": "2021-03-29 15:27:31",
"client-ip": "10.250.0.162",
"username": "user:subject",
"device-type": "win",
"device-ip": "xxx.xxx.xxx.xxx",
"port": "50560",
"ingress-bytes": "0",
"egress-bytes": "0",
"ingress-packets": "0",
"egress-packets": "0",
"connection-end-time": "NA",
"connection-duration-seconds": "0"
}