Now that IS unusual. I've battle tested the elementals, and haven't come across any issues. I see you're in the forest section of the caverns, so I tested battling them in that area as well. I also noticed you're in the process of escaping while they attack, so I've tested that. I tested using berserk, forcing the elemental to use a physical attack instead, and I've tested silencing the elemental, but I can't seem to replicate the bug.
To be thorough, what equipment are you using? Are you attacking with any specific skills or spells before this bug occurs? What are your characters levels, and what level are your spells? Specifically, what level is Grey's Wind spell, and how many uses does it have?
Also, does the bug occur before or after the attack animation? If it's after, is there a particular actor that the elemental usually targets? If it's before, how far into the attack does the elemental get? Does is show the magic circle under the enemy to show that it's trying to use a spell, or does the bug occur immediately after the gauge is full?
EDIT: Also, thanks for playing the game! You sure got through it pretty quick, I'm impressed. I hope you've enjoyed it.