ok it seems like sharpness also contributes to this bug. what was your sharpness setting ? if you set sharpness strength to 0 and saturation to 1.0 then there should be no holes at all.
You can also post process added sharpness onto your video in some compositing app (after effects/shake/whatever). Marmoset renders looks so sharp thanks to it's sharpness post-process.
I don't think the spike would need hard edges... It's shading looks decent from what I'm seeing there. Anywhere you have those sharp angles though, they should be separated into different groups. (I don't mean sharp as in the spike's point sharp, I mean sharp like perpendicular lines)