According to spec:

https://github.com/mongodb/specifications/blob/master/source/retryable-writes/retryable-writes.md#command-monitoring

In accordance with the Command Logging and Monitoring specification, drivers MUST guarantee that each CommandStartedEvent has either a correlating CommandSucceededEvent or CommandFailedEvent and that every "command started" log message has either a correlating "command succeeded" log message or "command failed" log message. If the first attempt of a retryable write operation encounters a retryable error, drivers MUST fire a CommandFailedEvent and emit a "command failed" log message for the retryable error and fire a separate CommandStartedEvent and "command succeeded" log message when executing the subsequent retry attempt. Note that the second CommandStartedEvent and "command succeeded" log message may have a different connectionId, since a writable server is reselected for the retry attempt.

(See comments below for more details)