The coins can easily look different from others produced from the same dies for the mere fact that people will go to some length to rough them up to disguise the 'facts'. A Diadumenian with some rough and tumble nicks and dents. Or maybe even a touch of acid to take off some of the buff newly made looks will make it hard for even an experienced collector to spot. As I was inferring previously the real money comes from making valuable coins. Silver denari of Severus Alexander in F go for $20. A silver denari of someone 'unusual' (Diadumenian or Macrinus) can fetch a few hundred even with some issues (bumps and bruises).
I enlarged the pics a bit and stood back aways (5ft). Macrinus looks very familiar. They list quite a few similar ones to this over in the German
ebay. The 'experts' frequently cite Serbia as the source of these. It may be there are several places putting them out.
I often wonder (especially with the shananigans I hear people attributing to SOME of the more notorious coin grading services) Why spend money on advertising for a coin grading service ? Better bang for the buck by sending someones cousin over in someplace in the world the money and equipment to knock out high quality fakes. Then the customers who scare easily will all come running to use that low cost low budget fly by night coin grading service that you set up in the basement !