bathrooms smell like Kitchen/Food

Hi, I have a relatively new home (build late 2018) and my bathrooms on 2nd floor and the 3rd-floor/Attic smell of the Kitchen(1st floor) which happens to be located below them. I am starting to wonder if my exhaust from the Kitchen and the bathrooms are connected and that the whole thing is somehow not vented to the outside properly or clogged. And perhaps maybe the air that should be pushed outside the house is blowing back into the bathrooms.

Is such a thing possible? Any advice?

regards,
Sam

source https://hvac-talk.com/vbb/showthread.php?2222257-bathrooms-smell-like-Kitchen-Food&goto=newpost