This is because the missing portion of Dyer St is under construction, and they're detouring traffic onto Dorance St and making it two-way (see here). I guess someone chose to just delete the under construction portions. Supposedly, this construction will be done by the end of October (according to this - search for "Dyer")...

I went ahead and fixed up the nodes, at least. Hopefully this won't give Validator anymore heartburn!