Sumo Digital has already acknowledged the problem above and say they're looking into it.
I've mentioned this on NeoGAF, but we're looking into the Wii U Boost Challenge and Ninja Tag issue (and any other non-race game mode). To cut a long story short there was a problem with the update which went live on Sunday - and we're working to get it sorted ASAP.
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Damn. Hope this is all live and well by the time I get my Wii U copy [at Christmas] then!
Yeah, I hope a patch comes soon.
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