Media Encoder is Creating Two MP4 Files From One Source

When I export a video as an MP4 using a modified Youtube preset, it creates two MP4 files. One contains the video as intended, the other has a set of numbers added to the end of the filename, and is 0 kb in size. 

Media Encoder was not doing this a week or so ago with the same preset when I would export MP4's. Any ideas why this might be happening. 

Thanks