Corruption removal formula is completely messed up
If you have less than 10 Ap, corruption removal items actually corrupt you. Even at very high values of Ap, corruption removal is rather ineffective. For example, at 50 Ap a blessed scroll of corruption removal might remove only 60% of one corruption.
The greater white unicorn's corruption removal is also affected by this nonsense. At low Ap she can corrupt you to death, and at some middling levels of Ap she doesn't remove all of your corruption.
EDIT: The corruption removal multiplier seems to be something like (10 * Ap - 99)/1000. Of course, for Ap < 10, this is going to be a negative number. For Ap = 10, corruption removal is 1000 times less effective than it was last patch. The break even point with the old formula (which penalized you for having high Ap) is at around 72 Ap - if you have less than that amount, corruption removal is less effective than it was last patch.