If you have tried other inks on the Fabriano and the problem still exists, maybe there's something wrong with the paper. My guess is the sizing of the paper may have been affected.
If the paper still works for painting, maybe you should just paint and not use ink on it.
If you want to use ink on it, maybe you can try treating the surface with Daniel Smith Watercolor Ground. It's supposed to add sizing to the surface so that ink and water can stay on the surface better.
@Baptiste Amsallem
Not sure what happened.
If you have tried other inks on the Fabriano and the problem still exists, maybe there's something wrong with the paper. My guess is the sizing of the paper may have been affected.
If the paper still works for painting, maybe you should just paint and not use ink on it.
If you want to use ink on it, maybe you can try treating the surface with Daniel Smith Watercolor Ground. It's supposed to add sizing to the surface so that ink and water can stay on the surface better.