Is this expected?

CL-USER> (ql:quickload "parenscript")
...
CL-USER> (defpackage :ps-user (:use :cl :ps))
#<The PS-USER package, 0/16 internal, 0/16 external>

CL-USER> (in-package "PS-USER")
#<The PS-USER package, 0/16 internal, 0/16 external>

PS-USER> (ps (let ((s-a))))
"(function () {

    var sA = null;

    return null;

})();"

Also,

$ cat foo.lisp
(let ((s-a))
(+ s-a 42)
(chain s-a (append-child foo)))

PS-USER> (ps-compile-file "foo.lisp")
"(function () {

    var sA = null;

    sA + 42;

    return sA.appendChild(foo);

})();

"

PS-USER>

Which is against documentation "Top-level LET and LET* forms will create new global variables, or overwrite the values of already existing global variables with the same name."

Please comment