Don't take the Atronach Perk in Alteration along with Conjuration. It makes you disappear when you try to conjure and you're vulnerable for a couple of seconds, plus your conjured minion doesn't appear.
Indeed and there's a http://skyrim.nexusmods.com/downloads/file.php?id=3352 for this. Nevertheless, Bethesda should correct this for all platforms, in the next patches -after all, it's all about flagging the spells not to be absorbed.