interpretation of pound (#) character inside a bracket expression inside single quotes inside backticks

[Poor Yorick]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc -m32
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' -DCONF_OSTYPE='linu
x-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu' -DCONF_VENDOR='pc' -DLOCALEDIR='/path
/to/bash-3.2/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H   -I.  -I/pa
th/to/src/bash-3.2_linux/bash-3.2 -I/path/to/src/bash-3.2_linux/bash-3.2/include
 -I/path/to/src/bash-3.2_linux/bash-3.2/lib  -I/path/to/include  -g -O2
uname output: Linux glnx011 2.4.21-37.ELhugemem #1 SMP Wed Sep 7 13:22:27 EDT 20
05 i686 i686 i386 GNU/Linux
Machine Type: i686-pc-linux-gnu

Bash Version: 3.2
Patch Level: 0
Release Status: release

Description:
        The pound character (#), when located inside a bracket expression inside
        single quotes inside backticks, is incorrectly interpreted as the bash
        comment token.

Repeat-By:
        (simplified version of code from current texLive distribution)

        TABSIZE=`grep -v '^[ #]' some_file`
        ./test1: line 3: unexpected EOF while looking for matching ``'
        ./test1: line 6: syntax error: unexpected end of file

        (original line, as found in libs/ncurses/include/MKhashsize.sh of texLiv
e)

        TABSIZE=`grep -v '^[ #]' $CAPS | grep -v "^$" | grep -v "^capalias"| gre
p -v
"^infoalias" | wc -l`

-- 
pooryorick