Non-unique dirs in sys.path

[Gisle Vanem]

I'm having some trouble understanding why my Python 2.7.9
has the '%PYTHONHOME%\lib\site-packages' listed multiple
times.

I cooked up this .bat file to demonstrate the issue:
   @echo off
   setlocal
   set PYTHONPATH=
   python -c "import sys; [sys.stdout.write('%%s\n' %% p) for (i,p) in enumerate(sys.path)]" | sort --ignore-case

which produces:

   f:\Documents and Settings\Gisle Vanem\Programdata\Python\Python27\site-packages
   f:\windows\system32\python27.zip    << !! doesn't exist, but okay.
   G:\Programfiler\Python27
   g:\Programfiler\Python27\DLLs
   g:\Programfiler\Python27\lib
   g:\Programfiler\Python27\lib\lib-tk
   g:\Programfiler\Python27\lib\plat-win
   g:\Programfiler\Python27\lib\site-packages   << !!
   g:\programfiler\python27\lib\site-packages   << !!
   ...

Why are these listed twice with different casing? One
would assume that Python on Win32 would be case-insensitive.
Some .pth-file to blame here?

I've checked that PYTHONPATH is not defined elsewhere. Like in:
   HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
or
   HKCU\Environment

-- 
--gv