Can't cast spells.

[MysticExarch]

So whenever I order Durance to cast a spell, and about 50% of the time when I ask Aloth to cast a spell, the character instead runs away. They go to some random spot, such as a corner, spaz out and slide sideways for a few seconds, and then cast the spell. However, they don't cast it on the target, they cast it in some second random spot, such as a wall or outside the map. 

 

I have no idea what might be causing this. Has anyone seen this? Is there fix? It's frustrating me because I can't beat the enemies without casting the occasional spell.