Steps to reproduce:
1. Enable streaming
2. Ingest a single video and run the default workflow, make sure to tick the "archive" box
3. The mediapackage will at some point (for reasons yet to be determined) contain an element with url rtmp://mhdistribution01-sbox.ethz.ch/matterhorn-engage/190276ef-dab2-488f-9c64-31a60c5b50bf/attachment-1/vonly_short.jpg
4. This element cannot be inspected and the job payload will be null, which is not well received by line 268 of the EpisodeServiceImpl.