Could also be that I am doing something wrong.
I copied the example and put it in a file called "CustomFusionRecipes.json"

Is this me doing something wrong or is this a bug in Draconic Evolution?

Ok looks like a recernt change broke the custom recipe system. It will be fixed in the next release. Also it looks there is a mistake in the example.
https://puu.sh/sESDa/dd535bb925.png
The comma should be after the quote