Sounds to me like a very ineffective version on Fairfight Anti Cheat. If you don’t know what it is look it up. It essentially uses statistics of a player to determine if they’re cheating. Examples include tracking players through a wall or inhuman accuracy. This anti cheat alone was defeated nearly instantly as players just used cheats in their advantage but not FULL advantage. ESP through walls but not actually tracking the player fooled Fairfight. This was also very much client and server sided. Battleye was the solution.