It's happening sometimes also with other amenities. It is a result of the overzealous AI-system ,
@Sean95 When guests write a review they are also prompted to answer questions about amenities. A previous guest would have been asked if there was free street parking and clicked yes. Then it shows up as a pop up on your listing asking if you have free street parking and you as the host click yes. Free street parking now becomes one of the amenities of your listing.