Having some more fun with htaccess again! - I have tired everyhting and cant get it to play...

Below is my code:

RewriteEngine On  

RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

RewriteCond %{REQUEST_URI} !(/$|\.) 
RewriteRule (.*) %{REQUEST_URI}/ [R=301,L]

RewriteBase /v2/

RewriteCond %{SCRIPT_FILENAME} !-d  
RewriteCond %{SCRIPT_FILENAME} !-f

# Admin Pages
RewriteRule ^admin/$ admin/index.php [NC,L,QSA]
RewriteRule ^admin/([a-z0-9\-]+)/$ admin/$1.php [NC,L,QSA]

# Super Admin Pages
RewriteRule ^master/$ master/index.php [NC,L,QSA]
RewriteRule ^master/([a-z0-9\-]+)/$ master/$1.php [NC,L,QSA]

# If none just normal page
RewriteRule ^([a-z0-9\-]+)/?$ users/$1.php [NC,L,QSA]


https://domain.com/ - should load users/index.php
https://domain.com/login/ (or any /XXX/) - should load users/$1.php

https://domain.com/master/ - should load master/index.php
https://domain.com/master/xxx/ (or any /XXX/) - should load master/$1.php

https://domain.com/admin/ - should load admin/index.php
https://domain.com/admin/xxx/ (or any /XXX/) - should load admin/$1.php

However, master and normal /xxx/ works, however /master/ returns Error 404?

Any ideas please