Back on topic now,
Nintendo have deleted a few levels a fellow maker on GameFAQs had up, but not known why.
http://www.gamefaqs.com/boards/805618-super-mario-maker/74145107
And a while back it also happened to TWO other fellow makers.
http://www.gamefaqs.com/boards/2000475-super-mario-maker-level-sharing/73725495
This one lost all his levels and stars.
http://www.gamefaqs.com/boards/2000475-super-mario-maker-level-sharing/73760352