Scattershot doesn't pay any attention to what you have targeted. Here's how its flow goes:
Expend one charge to randomly select up to three different enemies at close range and shoot one arrow at each of them.
1. When you push the button, you detect all enemies in a short area in front of you, and stuff them all in an array.
2. If there are more than zero enemies in the array, randomly select 1 enemy out of that list.
3. We remove that enemy's name from the array.
4. We attempt to fire an arrow at that enemy.
5. We repeat 2-4 two more times.
That said, if the enemy it found is moving or ends up blocked or anything to that effect, arrows can miss, just like any other ranged attack. We'll keep looking into it, like I said we've got some things we're investigating.