I have a 2017 Škoda Octavia. Yesterday my wife cleaned the inside of the car and while she was  doing this the radio came on even though the key was not in the ignition. Since then, the infotainment system will stay on when the ignition key is removed and it has to be manually switched off. Any ideas why this is happening?

Mine is keyless but if the car is turned off it will stay on until i open the door. Then it shuts off.

I’m afraid that doesn’t work with mine.

Well Try a factory reset to clear any settings 

Turn the ignition key to the on position. If the radio is off then manually switch it on. Now remove the key while the radio is on and it should switch off automatically and should also start automatically when you reinsert the key and turn the ignition back on. Easy peasy.

Thank you all. The suggestion by brigades worked so I did not need to factory reset.