I don't know if it's a bug or a feature, and honestly I don't really care. Right now, it's baggage the Phalanx doesn't need.

Speed is king in Rome. Flanking and charge bonuses so outpace everything else that it's already very, very hard to use infantry tactics effectively. No unit suffers from this more than the Phalanx. Slow to move, slow to turn, and very vulnerable from anything but the front, the Phalanx is the most vulnerable unit on the battlefield. Cavarly crush them. Archers rape them. Even other infantry units engaged from the front tend to bleed around the side and inflict hurt, because as currently implemented, the Phalanx is a defensive tool that doesn't serve as an offensive meatgrinder.

The deck is already massively stacked against the Phalanx. Their only hope is careful positioning. Is it really fair to take even that away from them via 'drift?'