Why aren't the bonus skill points being added?

Here's a question. I've played with characters that enhance specific creatures based on their level multiple times, and I only recently decided to investigate how this works. I found that, for example, a dendroid soldier upgraded to level 10 (+ bonuses for this to attack, defense, etc.) in the army of a hero who makes such dendroids even stronger, only receives skill bonuses based on its own level. The additional +8 attack, +8 defense, and damage that the hero provides are not taken into account by the game. At least, this was evident through simple calculations.
Is this a bug, or is there something in the WOG settings that needs to be enabled correctly?
P.S. Health is calculated correctly (bonus for creature level + bonus for hero level).