This is weird, I am not able to reproduce the bug all the time and therefore I'm not sure what causes it. 
I'll apply the patch and if I can finger point exactly what causes the bug if it happens again, I'll tell you.
Thanks a lot!

> From: rgm@gnu.org
> To: felix.descoteaux@hotmail.com
> CC: 17563@debbugs.gnu.org
> Subject: Re: bug#17563: 24.3; Can't kill EShell buffer, "Text is read-only"
> Date: Fri, 23 May 2014 13:31:34 -0400
> 
> felix d wrote:
> 
> > 1. Type something passed the prompt sign in EShell, to the left. (which ispermitted by evil-mode I guess...).
> > Screenshot: http://i59.tinypic.com/33vitnd.png
> > 2. Switch buffer, do something else.
> > 3. Then try to kill EShell buffer (through ibuffer or anything else) andget warning: Text is read-only.
> 
> I could not reproduce this, but it sounds like fixed bug
> 
> http://debbugs.gnu.org/13963
> 
> Please either try the Emacs 24.3.91 pretest, or apply the patch from
> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13963#23
> 
> and recompile em-prompt.el.
>