[Fate]

If you look in the manual, movement and battles are two distinct things. There seem to be three situations flying around now, and I will answer them according to the manual.

1) Army 1 moves from province A -> B and Army 2 moves from B -> C. They will never meet, because movement is before battles.

2) Army 1 moves from A -> (indy)C and Army 2 moves from B -> C. The battles should be in random order, according to the manual.

3) Army 1 moves from A -> B, and Army 2 moves from B -> A. The armies have a random chance of meeting based on their sizes. If they meet they randomly fight in either A or B (50/50 chance).