Help with minor league managers losing skills

I dont play too much and this is my first post, as I can usually find the solution to my problems by searching the forum.

I'm in the 4th year of a standard fictional game. As other teams release really good managers or coaches or scouts, I'll hire them for my minor leagues. However, it seems that later on in the year, I wind up with 2 (of my 6) minor league managers that have far lower skills. Unfortunately, I can't remember the names, so I don't know if they are the same managers who have lost skills or if the good managers quit or were somehow fired then replaced with inferior managers.

The good managers had most of their ratings 15+, the bad ones have ratings of 6-9. This does not seem to be affecting my hitting or pitching coaches or scouts.

Can anyone exlpain this for me or point me in the right direction. Any help is greatly appreciated.

[Nutlaw]

Duplicate post.