Hello Michael,
When you use bscan to restore jobs and files information from a volume into catalog, a new jobid is created for the original jobid (the jobid that used the volume for its backup). This is why you have the JobId 687 and not the original one. This is the JobId that you will find in your Job table. And this is the jobId that Bacula will tie to your media in JobMedia table.
If the bscan operation is usual for you, I would recommend you to have an Admin Job doing prune operations of your jobs scheduled in an adequate date/time for your environment.
Also, I would remember you that you can use bls/bextrac/bscan to restore the directories/files without restoring the volume/job info into catalog.
Best regards,
Ana