Traded positions

So today I got a warning message at the end of a ranked match. It read, "Traded position: You played a different position than you were assigned. You earned LP for the position you played. Frequent position trading could lead to deactivation of positional matchmaking." I can see why it is a thing. It would stop people from boosting a different position by playing their best position. But still, I was assigned top and my jungler got autofilled. So I traded him and we ended up winning the game. That's called adapting. That's part of the key elements to games like this. When you get a warning for using one of the core elements of the game, that should show there is something seriously wrong with the ranked system...