When calling the binary, the cardanoOutputDir field is processed before the call to cardanoTestnet, in Testnet.Prperty.Run:testnetProperty, where it is integrated in the generation of the configuration.

When calling cardanoTestnet directly (e.g. for testing purposes), the argument is ignored, and the configuration is generated without using it.

My proposal for fixing this issue would be to delete one of those arguments in the call to cardanoTestnet, or to sanitize its inputs altogether.

Another option would be to push the code for honoring cardanoOutputDir down to cardanoTestnet