Don't know why, but the jobs in question exists in two languages:

The script in EPiServer.Data.Resources.SqlUpdateScripts.zip\9.8.3.sql doesn't handle more than one entry:

...

SET @OldId  = (SELECT pkID FROM tblScheduledItem WHERE TypeName = 'EPiServer.Notification.NotificationDispatcherJob')

...

Hi Espen,
We are looking into this, could you verify that it's only the NotificationDispatcherJob that has multiple entries and not all job types?

Thanks,
Henrik

Hi Henrik, thanks for the feedback

NotificationDispatcherJob and NotificationMessageTruncateJob had duplicates, all other jobs were fine.

It's hard to tell exactly when the duplicates appeared though. We usually install every update on this site.

Espen

Hi again,
We can confirm that the upgrade script fails in this case as it was written with the assumption of a single entry per type and namespace. This script was somewhat ironically added to prevent duplicates of the same job but in different namespaces. We will modify this upgrade script so that it won't fail if there is multiple entries in the database but we have yet to find any reason for why you ended up with multiple entries in the first place. This is also not something that's been reported before. We will keep looking, but if you can think of anything that you have done to cause this state, please let us know.

Thanks,
Henrik

Hey. I'll of course notify you if I should think of anything that could've caused this. It's hard to tell when it happened since there's no "CreatedDate" type column in the table, so we could pin it to a certain release. I'd have to look through old sql-backups, but that is not easily achieved in the environment in question.