Question on $@ vs $@$@

Hello.

I include bug-bash even though i think bash is correct, but there
lots of people of expertise are listening, so, thus.
Sorry for cross-posting, nonetheless.
Given this snippet (twox() without argument it is)

  one() { echo "$# 1<$1>"; }
  two() { one "$@"; }
  twox() { one "$@$@"; }
  two
  two x
  twox
  twox x

i get

  $ dash shbug.sh
  0 1<>
  1 1<x>
  1 1<>
  1 1<xx>

  #?0|kent:tmp$ busybox.static sh shbug.sh
  0 1<>
  1 1<x>
  1 1<>
  1 1<xx>

  #?0|kent:tmp$ bash shbug.sh
  0 1<>
  1 1<x>
  0 1<>
  1 1<xx>

(This is busybox with my arithmetic patch, built on April 20th.)
Unfortunately my MUA is also bogus :(

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)