while the wording wasn't clear by referring to "job File", the issue was dismissed too soon.
i Have had the same issue also, scheduler shows a job and refers to a specific NSQ file when hovered over, you go check the folder the file is indicated as existing in and it doesn't exist the file is(and has) been removed by us, the service log shows no record of it loading that NSQ for a schedule but it still exists in the scheduler.
you can start and stop the nprinting srvc, even restart the machine and still it will show the schedule.
in this instance the file it was in was copied out renamed, all schedules update to new names, old file deleted then put back in the job folder ,so it's like its hooked up internally that the unique ID was from an old file.
a Text search in the content of the new NSQ has no reference to the named schedule.