.
In RTW.exe the AI will reinforce its own territory with naval unit transport. Happened to me: A SSbQ stack came from Africa to relieve Lilibeo. Once the province is yours, it will never manage to disembark, although it does transport.

A full SSbQ stack with a general loaded on-board a fleet slept for decades at the Italian coast when those parts belonged to the late SPQR.

The original bug is with disembarking onto foreign territory.
.