I didn't immediately crash or anything, so I just typed my comment and sent the error report and finished the battle. But as soon as my little skirmish was finished I noticed another copy of my character floating around near the entrance!
The one I'm highlighting is the one I have control over. The one next to the exit is some weird bugged out version of me. Whenever I move my player, the clone seems to visually warp towards where my controlled one is, before warping back to his spot.
It has a colored border just like mine and it doesn't seem to be acting independently. Leaving the area doesn't make him disappear. I'm gonna try doing things like exiting the game and if it doesn't fix itself, continue playing this file till endgame anyways (so close) and see if this file bugs out anymore. If anyone wants more details from me feel free to ask. I couldn't screencap the exact LUA error unfortunately.