Mutiple-Target Skill Doesn't Work

When I play team mode, my Draconius's Wild Fire sometimes attacks only one monster. It happened to me so many times. I am not sure it happens with me only or not.

that's happened to me a couple times as well and heres my theory, I think those moves work the same way as moves that hit more than once (psychic moves, thunder blast, slash etc...). the way I figure it is each one of those moves have a set chance of hitting more than once, some higher than others. in the same way moves like earth quake, wild fire, and tsunami have a set chance of hitting both or just one monster. what this pertange is I couldn't say for sure but that's my thinking at least