Post a screenshot, of the end of match statistics.

As I think you're likely just noticing the corners, or noticing some of them, but they definitely won't be consistently scoring 80% of corners. Even in games where I win by 5+ goals my opponents usually have 3-5 corners. In close games they'll often have more.

Assuming that's consistent in your games as well, an 80% strike rate on corners would mean your opponents would probably be scoring 3+ goals every game. Which would be very difficult to compete with, and I doubt you'd be winning many/any games.

So it's probably just a case of you misreading the statistics (Or the game only showing the comments when your team is about to have a goal scored against them).