Propane smell from air
 

I have a 2021 f-150 base model stx with 42,000 miles on that I’m having issues with the air smelling like propane. I have took it into dealer ship and they can’t find anything I had both the techs smell the smell I was smelling and they ran different tests and still haven’t found anything. They recommended me taking to another dealership for 2nd eyes but I won’t get in until January. It just worried me because I have a baby with me that I drive along and don’t want her breathing that in. Any issues or ideas that anyone knows about or have had a common issue ?