But if it the player is already in front of the attacker, that means the attacker is already in an offside position if he is in the other half. Offside trap only applies when an opposing attacker is in your own half. When all your players are in the opposing half, this means that any opponent lurking in your own half is already offside. They will have to move back on the middle line. Your players will move forward to cause an offside only if they are in your own-half and an opposing player is in certain positions in your own-half.
By the way, have you noticed that the players are always in front when high pressing is used in this game?
I am not saying that it is 100% sure that the combination of offside trap and high pressing is very good or bad in this game. A lot of testing needs to be done. Also, there are other factors that need to be considered, for instance other orders used, formation used, the formation of the opponent, the qualities of the players and so on.