I have to say, regardless of how it *used to work*, my friends are experiencing the same behavior as OP.

We have a shared server we play on, and they have also started worlds and used their characters on both, but we've only defeated bosses on the shared server. For a "fresh" single player start, they created new characters and grabbed some early game grinding stuff (leather scraps and crap) to take to their solo world. On brand new worlds they were getting draugr and slime attacks at their newb starter bases with those fresh characters.

If that is not how it's supposed to work in the latest .11 then *shrug* weird.