How do I get non-existing Joomla URLS redirected t

Brief: Any search friendly URL that starts with a number goes to a broken page that shouldn't exist instead of custom 404 Error Page

Details: Any partial existing url & random characters seems to return a broken page and not the 404 page.

Example non-exiting urls that correctly goes to 404 Error page: http://www.shareandcare.org/asdasd or http://www.shareandcare.org/a22sdasd

Example non-existing or partially existing urls that SHOULD go to 404 Error page: http://www.shareandcare.org/17-progsdsadsad and http://www.shareandcare.org/27-progrsdsads

Because they start with a number they load a broken page that in my opinion doesn't exist. It's as if they are looking for a joomla id, but even so why would it appear broken?

My htaccess is as follow, any solutions would be appreciated:

# @package      Joomla
# @copyright    Copyright (C) 2005 - 2013 Open Source Matters. All rights reserved.
# @license      GNU General Public License version 2 or later; see LICENSE.txt
##

##
# READ THIS COMPLETELY IF YOU CHOOSE TO USE THIS FILE!
#
# The line just below this section: 'Options +FollowSymLinks' may cause problems
# with some server configurations.  It is required for use of mod_rewrite, but may already
# be set by your server administrator in a way that dissallows changing it in
# your .htaccess file.  If using it causes your server to error out, comment it out (add # to
# beginning of line), reload your site in your browser and test your sef url's.  If they work,
# it has been set by your server administrator and you do not need it set here.
##

## Can be commented out if causes errors, see notes above.
Options +FollowSymLinks

## Mod_rewrite in use.
RewriteEngine On

# This attempts to block the most common type of exploit `attempts` to Joomla!
#
# Block out any script trying to base64_encode data within the URL.
RewriteCond %{QUERY_STRING} base64_encode[^(]*\([^)]*\) [OR]
# Block out any script that includes a <script> tag in URL.
RewriteCond %{QUERY_STRING} (<|%3C)([^s]*s)+cript.*(>|%3E) [NC,OR]
# Block out any script trying to set a PHP GLOBALS variable via URL.
RewriteCond %{QUERY_STRING} GLOBALS(=|\[|\%[0-9A-Z]{0,2}) [OR]
# Block out any script trying to modify a _REQUEST variable via URL.
RewriteCond %{QUERY_STRING} _REQUEST(=|\[|\%[0-9A-Z]{0,2})
# Return 403 Forbidden header and show the content of the root homepage
RewriteRule .* index.php [F]
#
## End - Rewrite rules to block out some common exploits.

## Begin - Custom redirects
#
# If you need to redirect some pages, or set a canonical non-www to
# www redirect (or vice versa), place that code here. Ensure those
# redirects use the correct RewriteRule syntax and the [R=301,L] flags.
#
## End - Custom redirects

##
# Uncomment following line if your webserver's URL
# is not directly related to physical file paths.
# Update Your Joomla! Directory (just / for root).
##

RewriteBase /

## Begin - Joomla! core SEF Section.
#
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
#
# If the requested path and file is not /index.php and the request
# has not already been internally rewritten to the index.php script
RewriteCond %{REQUEST_URI} !^/index\.php
# and the request is for something within the component folder,
# or for the site root, or for an extensionless URL, or the
# requested URL ends with one of the listed extensions
RewriteCond %{REQUEST_URI} /component/|(/[^.]*|\.(php|html?
|feed|pdf|vcf|raw))$ [NC]
# and the requested path and file doesn't directly match a physical file
RewriteCond %{REQUEST_FILENAME} !-f
# and the requested path and file doesn't directly match a physical folder
RewriteCond %{REQUEST_FILENAME} !-d
# internally rewrite the request to the index.php script
RewriteRule .* index.php [L]
#
## End - Joomla! core SEF Section.

If you copy/paste the following code into a .htaccess file, all requests for non-existing files or folders will return the contents of your index.php file.

<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ / [L,QSA]
</IfModule>

The meaning of every line is the following:

RewriteEngine on: Enable the runtime rewriting engine.
RewriteCond %{REQUEST_FILENAME} !-f: The rewriting will take place is the requested filename is not a regular file or if the file doesn't exist.
RewriteCond %{REQUEST_FILENAME} !-d: The rewriting will take place is the requested filename is not directory or if the directory doesn't exist.
RewriteRule ^(.*)$ / [L,QSA]: If the above conditions both match (the requested file isn't a file, isn't a directory, and doesn't exist) then the URL will be rewritten to the root of your website.
The "L" means that the rewriting process should stop immediately after this rule has been applied and the "QSA" means that any query string from the original request URL must be appended to the rewrite target.