So you see a general with 4 priests somepoint in the mid game.
That does not mean they are 'exploiting' the minion bug. It means they legitamitely upgraded their priests, and the old ones did not go away.
When I upgrade from monks to bishops, I'm left with 2 monks, and 2 bishops. I run around with all four untill the monks die, which is normally fairly quickly. What else am I supposed to do with them? I don't rebuy them after they die, nor do i stack 8 priests.
So please stop accusations of 'Cheater!'.