RE: Is this a bug of Emacs-Lisp?

[Drew Adams]

    If you really want to create a new cons cell every time (dummy) runs,
    you'll have to explicitly do that in the function:

        (defun dummy () (copy-tree '(1 . 2)))

Sure, but that's really doing things the hard way! If you want a new cons
cell, then function `cons' is your man - no need to beat around the bush:

 (defun dummy () (cons 1 . 2))