The Edit Layer State Dialog> Add Layer to Layer State> indicates "All layers are already included in this layer state." for all of my layer states!
I tried something else:
I restored a layer state, opened Layer States Manager, clicked the Update button.
Even though the the column titled "Same as DWG" still has "No" as the value, the Name of the Layer State now appears in the pull-down.
Maybe there is some buggy behavior?