Question about spellcasters and un-learning spells

I never heard of a way to unlearn a spell. Perhaps you could check your sims' hidden traits to see if there is a hidden trait for learned spells.

Normally spellcasters don't cast spells automatically. The only spell I have ever seen a spellcaster use autonomously is a cc spell to upgrade object. My sims house ended up with all objects fully upgraded before I figured it out. I think I will remove this cc spell next time I play a spellcaster.