This is a proper track dropout.
Note the amount of material surrounding the slot for the hub. Also note that the section the hub clamps onto is not machined thinner as if to accommodate a shim or axle-guide. Also note that it doesn't have any holes drilled into the load-bearing portion.
I can't say what broke your dropout, but from its appearance its failure doesn't surprise me. Maybe you can get Cinelli USA to warranty it.