Not the enemy units but your units. Sometimes your units take a detour or are standing at a tile which is tacticalwise less favourable. In one battle my champion moved towards the enemy unit like this:
starting side player: Champion--> enemyunit enemy starting side
My unit had plenty of movement to move to the backside of that enemy unit. Because it choses that side I had to spend another turn to reach the other enemy units (which were archers). If the player could see and choose the attacking side (like below) it would be more tactical:
starting side player: enemy unit<--Champion enemy starting side