I have been working on flushing out "stuck" transcodes from the running transcodes recently... ones that had been in a "started" status for weeks or months, and were probably interrupted by a server reset. Among these I've found a few (https://commons.wikimedia.org/wiki/File:Rhaeadr_Fawr,_Abergwyngregyn,_Gwynedd,_Cymru_(Wales).webm is an example) that are permanently "running" and not resettable due to this.