Do you have a client that connects to a server?
If the answer is yes, that's the deal, but, all is not lost
It's a bit messed up, and an absolute nightmare for the devs to fix, apparently, so for now, we have to put up with it. The problem arises when the client syncs back to the server... it messes up the PlaylistID of existing smartlists.
The work around,
on the server, is not to use the wizard, but instead, enter a 'custom' rule along the lines of:
p="regular"
That would include tracks from any playlist with "regular" in its path or name. Just pick a rule that uniquely targets the playlist you want.
If any of that isn't clear, just shout and myself, or someone, will be a bit more verbose.
Using a shortcut rule like that protects your smartlist from the client syncing shenanigans.
-marko