Save games from Dolphin exported to Wii U shows as "?"

[KHRZ]

So I had a NAND dump from my wii, exported saves to virtual SD through Wii Menu, hoping these would be legit enough for the Wii U. But they show just as "?" in the Wii menu of Wii U (tried 5 games), and when I copy them over, it says they may not have been copied (they weren't). It works fine if I do the same transfer from my real Wii. Although funnily, the twilight hack save shows fine in the Wii U. Does anyone know the problem?