This was raised by my guild member @Astaerus back in October.
I also experimented with Frost Mage and 3 x Greeds to see where the Frostbite landed and in very seldom cases (less than 5%) it did actually target a different troop other than the first.
Still this is nowhere even close to call this a “random enemy.”
@Kafka did mention she filed a bug report however we weren’t updated on the progress.