I have a 3.0.9 Linux mongod with Kerberos connected to an AD server. I ran 3.2.3 mongoimport.exe in Windows and did not specify appropriate Kerberos credentials in the following:

.\mongoimport.exe --host <mongod> --authenticationDatabase $external --authenticationMechanism GSSAPI --db <db> --collection <collection> --file <json>

After it ran, it output:

imported <number> documents

However, the documents are (correctly) not imported and the server log (correctly) states:

Unauthorized not authorized on <db> to execute command

mongoimport.exe should instead state a security error. 3.0.9 mongoimport.exe states the error that appears in the server log. 3.2.3 should function as 3.0.9 does.