Invisible 'pending' scheduled jobs

PSU 4.2.19 is busting my ass with an issue I first noticed a week ago.

Some jobs neglected to run on their schedule, no errors, no trace of them in the Jobs page.
Invoking the scripts manually though, immediately creates a job that is Queued, and also now the original scheduled job begins, supposedly on its schedule.

The job here, was scheduled 6 hours earlier, and appeared out of thin air when I ran the script manually.