I cannot duplicate this issue.  Using  vim -u simple.vimrc, which is:

set nocp
filetype plugin on
let g:netrw_liststyle    = 3  " tree

I used vim 7.3.1237, netrw v150b (see 
http://www.drchip.org/astronaut/vim/index.html#NETRW).

[deleted comment]

True, with you vimrc I can not replicate it too.

Sorry, for reporting it.
I will try to locate the problem.

Hi,
I found the minimal .vimrc where it fails:
Store this into simple.vimrc

set nocp
filetype plugin on
let mapleader=","
let g:mapleader=","
let g:netrw_liststyle    = 3  " tree


and run steps 1-6 and REPEAT steps 5-6 (the same as 2-3) for THIRD time.
I have no clue whi mapleader "," break this.

Btw. you can write me on the ondrej dot platek at gmail dot com.
If you need quicker answer from me.

And I found even simpler simple.vimrc 
and you need to run :Explore and open text.txt 3 times!
echo test > text.txt
vim -u simple.vimrc text.txt
" run 3 times :Ex   and then open text.txt
" the content of simple.vimrc :

set nocp
filetype plugin on
let something_other = "."
let g:netrw_liststyle    = 3  " tree

I can confirm this issue. Vim 7.4.26 MS-Windows 32-bit (console and gvim)

It is not related to mapleader. Necessary and sufficient steps to reproduce:

vim -u NONE -N -c 'runtime plugin/netrwPlugin.vim | let g:netrw_liststyle = 3'

:Explore

Open any file (say .bash_profile) using <enter> in netrw.

Return to netrw using :Rexplore

In netrw explorer, open the *same* file using <enter>.

Return to netrw using :Rexplore again.

For a third time, open the *same* file using <enter>.

The buffer is now blank. User must undo the change.

Hello!

Please try v150i of netrw from my website: 
http://wwww.drchip.org/astronaut/vim/index.html#NETRW.

Regards,
C Campbell

Thanks. The website says:

Updated Nov 09, 2013 (v150i)

But but netrw.vba says:

let g:loaded_netrwPlugin = "v150h"

I downloaded from this URL: 

http://www.drchip.org/astronaut/vim/vbafiles/netrw.vba.gz

And compared it to the source of the previous version from this mirror:

https://github.com/eiginn/netrw

And there are no differences.

I tried this anyway:

:NetrwClean!
:e ~/Downloads/netrw.vba
:UseVimball ~/.vim/

But the issue persists.

Try again -- I loaded the file onto my website again; I've downloaded it via 
ftp and via my browser, and was getting v150j.  Make sure your browser's cache 
history is cleared -- sometimes browsers "save time" by not bothering to 
actually download files when they have a cached copy.

Regards,
C Campbell

Thanks, it seems to be fixed!

Will this be merged to Vim trunk any time soon?

I let it stay on my website for some time, collecting bug reports, fixing 
problems, and occasionally extending it.  After its "properly aged", I send it 
on to Bram.  I've already got one bug report against v150j (which I won't be 
likely to be able to address for a couple of days).