Enemies dont use them at all. Atleast in the first part of the game and i do have the spells long before enemies or that single poor enemy in the graveyard.
In reality.
To be clear - i have the spells as bought scrolls, not the skill. From as early as level 2, as soon as i got to Cysael.
And apart from that single sorry sod in the graveyard i cannot remember seeing any enemy using that spell at all. Maybe at some later stages there are one or two who cast it but thats it.
Altogether thats a far lesser issue and just an additional problem, a related consequence of the main problem i described.