It was obvious this would have happened when they agreed to give teacher grades.
Not all private schools will have overinflated, and not all state will have under estimated, but on average it was obvious it would happen.
People were hailing it at the time as a great triumph but it clearly was only a triumph for some.
Those whose schools were honest have to battle against others with inflated grades and the assumption that they themselves have inflated grades.
One local private school gave everyone 9s across the board. They don't generally expect many under 4 grades, but they have a normal distribution in 4-9 grades.
It's not been brilliant for those kids either. About 15-20% that I know of have redone the year 12 after picking a levels that they didn't expect to be allowed to do, but suddenly could. (no 6th form so they had to change school) Then when they started the course they struggled massively.