Enroute/Schduled to XYZ airport doesn't make sense

I frequently see an aircraft listed under enroute scheduled to an airport when in fact the aircraft landed last night. Can anyone define what how the lists work when you are viewing an airport activity? The titles seem intuitive enough but I see wierd results.

Sometimes operators will file multiple flight plans for one flight and the operator or ATC will neglect to cancel the ones that were not operated.

We don’t hide the unflown plans, because for all we know the aircraft is going to fly ABC-XYZ-ABC-XYZ and we want to make sure the second ABC-XYZ segment appears. They are cancelled in about 24 hours and will disappear from the boards then.