Different odor

It can evolve, sure. High temps will evaporate the more volatile compounds and hasten the demise of the molecules with high boiling points, too. Some of the molecules that create smell and taste evaporate quickly in the mid-70s F. Not much you can do about those while growing, but storing can be done in a way to preserve them a while. Others have BPs as high as 400+F. But, it's probably not just evaporation why it changes over time. Also, what you smell is evaporated molecules. The very existence of the smell means it came off the plant. It is happening at all times. just as when you smell a fart molecules from some person's asshole just went up your nose. Sweet dreams. this stuff has mass. it's physical despite not seeing it.