I do notice that in my games, it's the script and a pesky Barbaroi Diplomat.

Funny, I don't see it happen that often though. Either it's the ALEX.exe or the Jebi's flaming spirit of Rhomiaoktonos, the Karchedoi often send their stack with Nellies straight at Messana and take it within several years into the game. Then they either sit there for the Barbaroi to attack (and fail due a combination of Nellies and Jebi's Rhomaiokonos Chapter), or have a go at the Syrakosai...