I recently experienced that some young players started growing faster after they reached 5th star...
Really ? I 've never noticed that.
Only this I wrote
Sometimes the 6* (but Q0 - Q1) player can hit a bigger number than some of the numbers he had when he was 5*
. Did you make some upgrade in your facilities - like training ground or grass when this happened ?
I didn't search if training ground affects training results.