Yeah, I figured it could be exploitable and did a few tests during combat... but... it doesn't work incombat, only if you have enough AP's to acutally double-cast.
As such, it can't exactly be called an exploit.
If someone found a way to do so, let us know, but I wasn't able to break the system using this, only as stated, had it make exploding things like waterbarrels in the tutorial dungeon more convenient
