is this a bug?

i have some reserves i train on purpose to enter negotiations in order to gain tokens by sellng them. since my player had reached quality 59,9%, i started training him in special ability. i do this many times. train them in ability or position. but today i played a friendly game and after the game instead of increasing in ability he gained quality and as a result he reached next star and now he is useless to me. its the first time it happens to me. is it a bug or something has changed?

Hey gkassimis, there are two training elements that always increase a player's core attributes instead of being added to an Ability/Role currently in training. These are the Man of the Match title (for the highest rated player in the winning team), and the daily Training Gift. Both of these add 4% to a player's attributes, and always to his attributes. Never to a Role/Ability.
Since you say that he gained quality after the friendly match you played then he was the top performing player from your team.

true, he was man of the match. never had this. cant believe my luck:(