When a player is in multiple places on a team roster and they appear in the leagueleaders command, that player will appear more than once but with the same statistics listed in the output. 

This can cause the leaderboard to become clogged up with multiples of the same player(s) without adding any new information.

(However, when a player is on multiple teams in the same league, it seems that the different instances of the player are tracked separately and have different stats.)