I've had an H-Factory 292M for a year or so and the only mark it has picked up is where I scraped one of the strap wires on it while trying to guide it into the hole.
The ceramic almost certainly won't scratch if it has been sintered correctly, what you usually see is the other material left behind on the surface - I suspect the mark on mine is actually steel left on the ceramic, not where ceramic has been removed.
Maybe there could be a rougue batch of cases if a couple of you have had similar issues and are sure you're seeing scratches/damage?
This is the reason
They are not scratches. They are material left by other object "scratched" by the hard ceramic of your watch
Try to clean it with some toothpaste and wáter. Try before in caseback I have not used before this system !!
ALE
Get a rubber pencil eraser and rub the scratches away, worked on all my matte finish ceramic watches so far, this one included