I have a problem with a file where the Grease Pencil fill materials won't render while the stroke ones will.
I tried the following : appending object in another file, switching sequencer in the Output > Post Processing panel, rendering using the compositing output.
I have another file with the same materials that works, so I think it might be a bug. Here is a screenshot of my scene :
And Here is the rendered image. As you can see only the stroke appears.
Here is a link with the blend file, and here is a link to a working file (The files are a bit heavy due to packed textures).
Thanks for your time.