Very informative, and gives me a very good idea of what the issue is.
I wonder if what's happening is that Shanghai Epic Music Entertainment who manage all the licenses from the big studios and practically have the monopoly on physical media production as well as distribution in Mainland China is simply overstepping their bounds when it comes to these small runs in terms of the artwork approval process. Maybe it's harder to get away with it with Disney or more normal-sized print runs like with HDZeta and BluFans so those go through all the regular hoops, but with a smaller company like Diskino, they've just said go ahead do whatever you want especially since the run is so low. The other thing to keep in mind is that a company like Diskino makes such small runs because they (so far) aren't factoring in an overseas market as well like with HDZeta and BluFans. This being the case, maybe Shanghai Epic doesn't see it as an issue since it's technically supposed to be isolated within Mainland China where they hold the power anyway. Again, gotta take into account how muddy copyright law is in China and how it isn't as cut and dry as it is in say the US or EU. I feel like the creation of a company like Shanghai Epic (who are a joint between some Chinese companies and Sony DADC) allows the big American studios to have a media distribution presence in the growing Chinese market, but without having to deal with the complicated cultural and legal boundaries of the Chinese market themselves.
That being said, could it be possible that many of the small South Korean companies who have very low-run "premium" releases may also be skirting on the edges of legality when it comes with artwork approval?