Corprus implementation is incorrect
So Corprus puts three effects on the character:
- Corprus (the disease)
- Corprus (drain int, wil, spd, pers)
- Corprus (fortify str, end)
What is supposed to happen during the Corprus cure is that all three of those effects get removed, the drained Attributes get restored up to one point below base value (unless the Drain was only one point, in which case they get fully restored) and the fortified Attributes remain at their increased value until they get damaged below the base value, after which they only restore up to the base value again.
What currently happens in OpenMW is that the first two effects get removed, but the Fortify effect stays, resulting in the increased Attributes being permanent and resistant to Attribute damage. Also, the drained Attributes get fully restored.
I've made an image to show the differences. The icons from Race and Birthsign are crossed out to highlight the effects of Corprus.
OpenMW 0.44.0 Revision c280a71b
On a side note, does anyone know if (and how) it's possible to fix a character by manually removing the remaining Fortify effect? I've tried various console commands such as RemoveSpellEffects, but nothing I've tried seems to work on this particular effect even of it works on others.