I usually play with the game audio turned down about halfway, but when I cast the Spiritual Tribunal spell, my audio gets turned back up to max. Apparently this happens for other people in the battle too, as my friends have said the same thing happens to them. I can fix it temporarily by turning the audio off and then back on again, but sometimes it will go back to max again after going through a load screen.
Yes, I've observed this personally as well. The music volume in particular increases significantly after using the spell though it seems to go back to normal after a short while.
