Tunneler's Dream superflat world has snow on top

The bug

Superflat worlds created with the Tunneler's Dream preset are generated with snow on the surface. That was not the case in previous versions.

Original description

When I try to make a Tunneler's Dream superflat world, it loads me into a Snowy Kingdom superflat instead. (Latest seed: -6780918275031299935) It's been this way through several patches now.