Pricop, is the OP your second account? Usernames are similar, and you replied him awfully quick.

For the actual question, it's normal for all your players to lose one star when you finish in the top 7 and get promoted. They are playing at a higher level and relatively are not as good as they are before. Regarding the 2* drop, I put it down to human error, he must have been 3* at first, or after.