Just tested it, with a game started from scrath on hardcore, when they levelled up from lvl 1 to level 2. DK gained 1 skillpoints and the Hero gained 2. (Opposite your situation)
I think it is a bug, it makes no sense giving one character twice as many skillpoints as the other. If it is a Hardcore feature (which I hope), it should be 2 skillpoints for each.
