This stack trace can be seen multiple times throughout the logs:
This may have to do with the optimistic lock exception, as they can usually be seen right above the log statements in question. The operation may be set to "running", then the job is updated and that update fails.
FYI - I call this the "RESUME job race condition bug", at our site. We get multiple of these each day because we resume at three points in our workflow (during the default ingest resume operations, a resume after trim-hold, a resume after our custom view publication before publishing to students operation)