The copyright of each map belongs to the mapmaker and not to CC, so there may be occasions where the mapmaker has offered their map to Grand Strategy too. However, some of their maps are a clear rip-off of those made and developed in the Foundry.
In some cases it's an indirect acknowledgment that CC has some of the best quality 'risk-variant' maps around, and in other cases it's blatant plagiarism. Whether the map is there legitimately or otherwise, I imagine it would be up to the individual mapmaker to vest/protect their own copyright
