Some people are exploiting the leaderboards. Last season it were 2 guys (2 necros - one support and one damage were listed in the solo leaderboards with a too good time to be true.) This season the are listed again, but not the only ones. Top 2 wizards are basically the same, they both are listed with the same level and time.
It seems like it is a question of time until others are getting in touch with the exploit.