I've stumbled upon a minor bug in the Mercenary War scenario. I'm playing with the newest 1.03 release candidate, but I guess the bug is already present in earlier versions of the game as well (this is the first time I've played the scenario, so I don't know for sure).
The bug occurs when choosing to go to war with Rome over Sardinia and Corsica. Afterwards, you get a decision to ally with the Sardinian and Corsican tribes (who were previously at war with Carthage). The Sardinian leader unit (the Princips) seems to be bugged in this event, as it spawns as a non-defined unit without stats. See attached screenshot and savegame.