Usually when you lock a group you can click (or drag) in front and to the left of the group for it to move forward, or to the side of there if you want to rotate.
Occasionally, however, when you click (or drag) the new location it shows seems to bear no relation to where you clicked. It will spin the group around to some random angle and it becomes hard to put them where you want.
It's not just because they're limited by terrain. Once the group has decided it's in random mode, wherever you drag on the map it will show the group at some weird angle. Even if you move them somewhere else during deployment it will still be in random mode and it's often impossible to put them where you want however many times you move them.
Does anyone know a solution to this?