Tonda (water carrier) gives massive skill boost
Before talking to Tonda who was assigned as water carrier my warfare and fist skills were at level 12 and 11. After talking to him these skills were boosted to 20 and 20. By loading the savegame again these skills were boosted to 18 and 20 after talking to Tonda. Restarting the game doesn't help as well.
I use the following mods that might conflict with this issue:
Spearmans Delight v 1.1
But as there is also a reddit thread that mentions this issue it doesn't seem like a mod conflict: https://www.reddit.com/r/kingdomcome/comments/80ccki/tonda_the_winch_possible_bug/