I believe that we've covered this particular error before in our discussions. This refers a job that failed under a previous version.
Whenever you upgrade VaultWiki, VaultWiki will look for failed jobs and try to execute them again, in case there was a related bug that was fixed in the new version. This is normal behavior. It occurs after the upgrade is successful; each job is tested one time.
In this case, the job itself doesn't appear to have a bug, but the process that queued up the job didn't include all the necessary information that the job needs. So the job will fail every time, no matter what we do.
In your database's vw_defer table, you will find a row where defer = 'rechapter'. You must remove this row manually, or you will see this message after every upgrade. Before you delete it, please write down the content of the dateline field as it will be useful for determining if we need to worry about more of these.
I don't remember if we've removed the record in the past when we encountered it, or decided to ignore it. If we ignored it, that's why it's here again now. If we already removed it, and here's another one, then something is still queueing up bad 'rechapter' jobs occasionally. If it's the latter, we should try to find the problem.