I've seen this -- last time the fix was
stop the job engine
delete the .sdf file with the data in it
copy the blank .sdf file to the same of the one you deleted
restart the job engine.
the SDF files (on my system) are in C:\ProgramData\Solarwinds\JobEngine.v2\Data\
I believe this is a 'cache' of the jobs needed to be run from the database, and it'll get repopulated.
Thanks for the reply, Richard.
I deleted and reinstalled the job engine but the issue keeps coming back. I'll repost when we get this solved.