Thank you for raising this issue. The problem here is a human one. As long as people are involved in the domain listing process, some will for some reason add fake listings. We've seen Undeveloped.com and DAN.COM being listed at all major marketplaces by different sellers so many times that we stopped fighting it. It's something that's very hard to battle, even with ownership verification in place.
What we're doing to prevent this from happening too often is to manage a growing list of active sites that we add to a blacklist. By doing this we prevent sellers from adding those domains to our inventory. We automatically also block the top 50,000 Alexa ranking sites for example.
And in a week or two, our revamped automated domain ownership verification will go live, however, as mentioned that won't make these cases disappear.
Lastly, keep in mind that no seller can benefit from adding fake listings and no buyer can become a victim of fake listings either since no transaction can be concluded without the seller actually delivering the domain.
We thank the community for its safeguarding activities and encourage our users to always contact us when in doubt over a seller profile or listing. Our staff will act diligently when needed.