Lags in commands when particular enemy is near

Please, Riot. Start doing something to the constant cheating or total failure in programming of client. For some weird reason one enemy team member nearby makes game react with 500 ms delay to commands given and mouse moves erratically. When I am dead or that player is not nearby, it works fine.

First: make game client and server communication such that client gets ONLY information player needs. It should NOT get any other information if you have any clue of security or want to remove 3rd party exploits. Sanitize IPs of every player from each other by making ALL communication go through server. This is BASICS of NETWORK SECURITY.