"false or mistranslated pages"
If we're talking fragments, don't forget 'incomplete'. "Why that's it! It's missing the (negating word,key ingredient,important warning)!"
"However, if a player gets attached to one of his agents it could pose a problem - after all, as far as I know, there is no way to remove the knowledge gleaned through occult study"
Overcoming the dark control doesn't have to be impossible, does it? But it would burden the character greatly. I'm reminded of Peace in the animation Wizards, how a mere touch allowed the Powers of Scorch to overwhelm him.
If your players don't like this kind of dramatic flaw, you need new players.
But, I'm speaking from ignorance of the rules you're playing.
Doug