Do you mean this link?
I don't see any duplicate cloud projects in my Google Cloud Console, but there seem to be some inconsistencies in what cloud projects are listed, depending on where I navigate. If I click in the drop down list in the header showing a project name, then I get a dialog with a list of projects. If I go to the resource manager, it seems like I get a much shorter list.
When I first started creating cloud projects, I had not defined an "Organization" so I've got projects listed under No Organization, that don't show up under my defined Organization. But this may be totally unrelated to your situation.