Looks like there is a defined (and unintuitive) order to healing afflictions.

There's some other stuff that seems to prevent units being healed but I don't know what that is about.

1. Battle fright, 50%
2. Feeblemind, 25%
3. Undocumented 137438953472, 50% heal rate, only healed if unit is not feebleminded as well
4. Disease, 50%
5. Crippled, 25%
6. Blind, 25%, only if unknown affliction 2147483648 not also suffered
7. One lost eye, 50%, only if affliction 2147483648 not also suffered
8. Weakness, 50%
9. Mute, 25%, only if unknown affliction 2147483648 not also suffered
10. Undocumented 2147483648, 20%
11. Undocumented 16, 25%
12. One lost arm, 25%
13. One lost eye, 50%, another chance
14. Chest wound, 50%
15. Limp, 50%
16. Never healing wound, 10%