Flight history only showing certain flights

flightaware.com/live/flight/SKW6748

Only showing routes in one ‘direction’ and not the opposite routes.
I know this is a common thing since I see it a lot. I don’t see anything in the FAQ about it. What is the reason for this?

It’s probably because this flight is scheduled to fly from ORD to BNA.

Return flight will probably have a different flight number

Make that 2 serious answers!!!