Well that's strange. Don't think we're going to find what's causing this.
I could reproduce it consistently with that file yesterday and the day before.
But not anymore today... Forgot exactly what settings I used, but I could export it fine now a couple of times.
However, I also ran into a couple of crashes but differently this time.
If I open MLV App, then add that file, change Chroma Smooth to 5x5 and export in DNG Fast Pass with DaVinci Resolve naming it crashed MLV App instantly.
Even before progress bar shows.
Was hoping this crash would happen consistently, but to my surprise repeating the process I got a couple of successful exports too.
I'm on the latest MacOS 10.14.5 by the way.
Sorry to bother with this!