I have a 2019 Mini so hopefully the same layout. It’s a physical button immediately below the circular central screen on the left hand side next to a button labelled mode. It’s got a diagram that looks like two cars and a radio transmitter. It’s easy to press by mistake and drove me mad when the traffic notifications came on seemingly by themselves. After searching through the infotainment menus and sub menus with no luck I pressed the button wondering what it did and the notifications stopped. Press again and they come back on.
I must have pressed it by mistake when I was cleaning the inside of the car.
Hope this helps.
