[1.1.5] Wierd message when trying Learn/Unlearn category

[Max]

Steps to reproduce.
1. Chose Cornac/Wyrmic.
2. Try to learn 'Higher Draconic ability' category, then unlearn it.
3. Unlearning will be successfully.
4. Invest one point to Str, then one point to Armour Training.
5. Try to learn 'Higher Draconic ability' category, then unlearn it.
6. Message '[Impossible] You cannot unlearn this category because of: -Weapons Mastery (not enough stat)' will be shown.
7. This message will be shown even after unlearning Armour Training.