Question mark expansion in echo statements busted?

[mod+bashbug]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: cc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DSHELL -DHAVE_CONFIG_H  -I.  -I../src -I../src/include 
-I../src/lib
uname output: Linux shrapnel 2.4.18shrapnel #15 Sun Mar 2 20:42:50 EST 2003 
i686 GNU/Linux
Machine Type: i386-pc-linux-gnu

Bash Version: 2.05b
Patch Level: 0
Release Status: release

Description:
        Can't have env variables with question marks in them?

Repeat-By:
 echo $BASH_VERSION
 a='LEFT'
 echo $a
 z='RIGHT'
 echo $z
 x='fubar'
 echo $x
 echo $a$x$z
 x='fub?ar'
 echo $x
 echo $a$x$z
 echo $a$z
 x='fubar'
 echo $x
 echo $a$x$z