AI lead motorized and mechanized groups,if traveling to a waypoint a few KM or more away will when encountering the enemy disembark the infantry as expected,but once the enemy is dead and the area clear,the infantry do not all get ordered back in their vehicle,but instead the vehicle either drives toward the waypoint leaving the infantry behind, or only some of the infantry get ordered in the vehicle,but some or all infantry are still left running after the vehicle while it drives off leaving them behind, the vehicle either speeding off or driving slower than normal but still too fast for them to keep up.
I'd expect them to re board the vehicle to continue to travel like in A2OA if they aren't close to their destination,not run on foot after a vehicle that is moving slower but still too fast to keep up and clearly leaving them behind and not maintaining formation.