I would prefer to release this worker and have processing pulling jobs (or the couch view) offset the retry by retry-after.  It would be reasonable to have this set to an hour, making this worker idle for an extended period.

Also without continuing to bump the modified fax_jobs:cleanup_jobs might reset the status thereby re-queuing  and blocking a second instance if failed.  If the second instance succeeds when this woke up might re-send a successful fax as fax_jobs works against a periodic fetch.