It appears the "Security Assist" suite of Server Behaviors can cause issues on MAC. Luckily the same functionality (improved) is available from the MySQLi->User Authentication Server Behaviors and those seem to work properly.
The solution is to use the MySQLi version of the server behaviors. Sorry for the inconvenience. The "Security Assist" server behaviors are really only there for legacy purposes to allow users to migrate to the new version. They will be removed in a future update in a few years, but for now shouldn't be used for application, only for updating.