this is a tough one to troubleshoot. the issue seems to be that there was no additional "metadata job created" entry after 14:57, 28 November 2014. a couple of thoughts:
1. the job runner picked up the job that creates additional media file jobs, but something went wrong - is there someone who could investigate what may have happened with the job runner?
2. something went wrong when the job that creates additional media file jobs ran. there should be an exception message in the php log - is there someone who could investigate that?