Can't disagree with anything you've said although tbh, I can't remember what my defensive settings were for specific kicks in that .pkm. I was experimenting in that game, trying (but failing) to create as many corner kick situations as possible, and then messing with the settings to see what happens.
If a team is going to leave a man unmarked, the corner taker should naturally play the ball to him and that player should then shoot, and often that player will score. That is realistic enough.
The problem is with the man being unmarked so often to begin with. I realize that in real life, players sometimes get confused and miss assignments resulting in soft goals. But it happens too often.
I have seen it where a player will just camp out in an obviously dangerous situation BEFORE the kick is even taken, and no one will move to cover him. It happens at least 2-3 times a game if you leave your defensive settings on default. If you mess with your defense, you can cut it down quite a bit but it still happens.
And their defense pretty much never covers my DMC lurking in the penalty box. I realize he is rather far away, but he is still close enough to be dangerous given that much space. And I am pretty sure I could actually scoot him up much closer the goal and he would still be uncovered, just haven't figured out the settings yet.
I think you are right that it has to do with overloading a zone and/or how the computer handles zonal coverage. It also happens on penalty kicks.
I think they changed something in the 10.2 patch to alter how the defense covers direct free kicks, which may include corners. Whatever it was, I think there's a bug in it that allows players to be completely unmarked too often and seems ripe for an exploit.
