problem with mentor system[Core]
 

i description bug of mentor system below:
menter have main class level 85 and not Graduated, he finish sub class quest and dual class quest (dual class still have menter buff) and then train dual class to level 86 and then Graduated, ok.
But when he swith to main class (still level 85) he can get mentor again, and menter buff will apply to dual class although he have level 86 or higher

Fixed, mentee won't graduate while not in base class.