Why doesn't getting a position other than jungle reset that summoner item to what it was?

Im tired of getting autofilled jungle where someone dodges and next time I get put in the spot I wanted. Multiple times now i have not fully realized that it switched my item out and that I need to switch it back. If it is going to automatically do it one way, why not the other? all it has to do is swap it to what it was before? is there a setting that Im missing or...