Recently in my PBEM game, I ordered two Corps to attack an adjacent region, pressed the synchronized move button, and only one Corps actually attacked, therefore I lost the battle. They were not attacking across a river or anything like that, both Corps had good cohesion, and they were both activated.
This is the second time this has happened in this PBEM. Previously I ordered three Corps to attack, and only two of them actually moved to attack.
I'm starting to question if I maybe forgot to move one of them, but I doubt that.. Are there any factors that can cause a Corps not to attack?