Make up can be confusing if you have no experience prior. I recommend just experimenting and you'll get used to it. Took me a week or two to get familiarized Edit awakening is hard to mess up except getting ideal children (classes abilities etc)
What I think is happening, you're targeting a monster outside of the abilities range and it can hit multiple monsters. It's attempting to hit the it off range but no variable so the damage gets attached to the closer monster, as well as their damage splat