change to try-completion behavior in 21.3?

[bigfaceworm]

My company has some RedHat systems (32 bit) and some 64-bit Suse
systems.
The Emacs on the two is behaving differently, and

64-bit version: 21.3.50.1
32-bit version: 21.3.1

The try-completion reacts differently to completion-ignore-case.

This code snippet:

(cons
 (let ((completion-ignore-case nil))
   (try-completion "w" ex-token-alist))
 (let ((completion-ignore-case t))
   (try-completion "w" ex-token-alist)))

Returns
("w" . "w") on the 32-bit machine

returns
("w" . "W") on the 64-bit machine

Is this expected (new) behavior?
Or did the computing support screw up the build/install?

Why should it ever return the capital letter W?

thanks,

BFW

ps. I don't use viper, a friend does and I'm helping him out.
pps. ex-token-alist is defined in viper-ex.el as:

(defconst ex-token-alist '(
        ("!"                    (ex-command))
        ("&"                    (ex-substitute t))
        ("="                    (ex-line-no))
        (">"                    (ex-line "right"))
        ("<"                    (ex-line "left"))
        ("Buffer"               (if ex-cycle-other-window
                                    (viper-switch-to-buffer)
                                  (viper-switch-to-buffer-other-window)))
        ("Next"                 (ex-next (not ex-cycle-other-window)))
        ("PreviousRelatedFile"  (ex-next-related-buffer -1))
        ("RelatedFile"          (ex-next-related-buffer 1))
        ("W"                    "Write")
        ("WWrite"               (save-some-buffers t))
        ("Write"                (save-some-buffers))
        ("a"                    "append")
        ("args"                 (ex-args))
        ("buffer"               (if ex-cycle-other-window
                                    (viper-switch-to-buffer-other-window)
                                  (viper-switch-to-buffer)))
        ("c"                    "change")
        ;; ch should be "change" but maintain old viper compatibility
        ("ch"                   "chdir")
        ("cd"                   (ex-cd))
        ("chdir"                (ex-cd))
        ("copy"                 (ex-copy nil))
        ("customize"            (customize-group "viper"))
        ("delete"               (ex-delete))
        ("edit"                 (ex-edit))
        ("file"                 (ex-set-visited-file-name))
        ("g"                    "global")
        ("global"               (ex-global nil) is-mashed)
        ("goto"                 (ex-goto))
        ("help"                 (ex-help))
        ("join"                 (ex-line "join"))
        ("k"                    (ex-mark) one-letter)
        ("kmark"                (ex-mark))
        ("m"                    "move")
        ("make"                 (ex-compile))
        ; old viper doesn't specify a default for "ma" so leave it undefined
        ("map"                  (ex-map))
        ("mark"                 (ex-mark))
        ("move"                 (ex-copy t))
        ("next"                 (ex-next ex-cycle-other-window))
        ("p"                    "print")
        ("preserve"             (ex-preserve))
        ("print"                (ex-print))
        ("put"                  (ex-put))
        ("pwd"                  (ex-pwd))
        ("quit"                 (ex-quit))
        ("r"                    "read")
        ("re"                   "read")
        ("read"                 (ex-read))
        ("recover"              (ex-recover))
        ("rewind"               (ex-rewind))
        ("s"                    "substitute")
        ("su"                   "substitute")
        ("sub"                  "substitute")
        ("set"                  (ex-set))
        ("shell"                (ex-shell))
        ("source"               (ex-source))
        ("stop"                 (suspend-emacs))
        ("sr"                   (ex-substitute t t))
        ("submitReport"         (viper-submit-report))
        ("substitute"           (ex-substitute) is-mashed)
        ("suspend"              (suspend-emacs))
        ("t"                    "transfer")
        ("tag"                  (ex-tag))
        ("transfer"             (ex-copy nil))
        ("u"                    "undo")
        ("un"                   "undo")
        ("undo"                 (viper-undo))
        ("unmap"                (ex-unmap))
        ("v"                    "vglobal")
        ("version"              (viper-version))
        ("vglobal"              (ex-global t) is-mashed)
        ("visual"               (ex-edit))
        ("w"                    "write")
        ("wq"                   (ex-write t))
        ("write"                (ex-write nil))
        ("xit"                  (ex-write t))
        ("yank"                 (ex-yank))
        ("~"                    (ex-substitute t t))

        ("append"               (ex-cmd-obsolete "append"))
        ("change"               (ex-cmd-obsolete "change"))
        ("insert"               (ex-cmd-obsolete "insert"))
        ("open"                 (ex-cmd-obsolete "open"))

        ("list"                 (ex-cmd-not-yet "list"))
        ("z"                    (ex-cmd-not-yet "z"))
        ("#"                    (ex-cmd-not-yet "#"))

        ("abbreviate"           (error "`%s': Vi abbreviations are obsolete.  
Use
the more powerful Emacs abbrevs" ex-token))
        ("unabbreviate"         (error "`%s': Vi abbreviations are obsolete.  
Use
the more powerful Emacs abbrevs" ex-token))
        ))