I'm trying to redirect newsletter URLs from my local server to an Amazon S3 bucket.

So I want to redirect from:

https://mysite.com/assets/img/newsletter/Jan12_Newsletter.html

to:

https://s3.amazonaws.com/mybucket/newsletters/legacy/Jan12_Newsletter.html

Here's the first part of my rule:

RewriteEngine On
RewriteBase /

# Is it in the newsletters directory
RewriteCond %{REQUEST_URI} ^(/assets/img/newsletter/)(.+) [NC]
# Is not a 2008-2011 newsletter
RewriteCond %{REQUEST_URI} !(.+)(11|10|09|08)_Newsletter.html$ [NC]
## -> RewriteRule to S3 Here <- ##

If I use this RewriteRule to point to the new subdirectory on S3 it will NOT redirect:

RewriteRule ^(/assets/img/newsletter/)(.+) https://s3.amazonaws.com/mybucket/newsletters/legacy/$2 [R=301,L]

However if I use a blanket expression to capture the entire file path it WILL redirect:

RewriteRule ^(.*)$ https://s3.amazonaws.com/mybucket/newsletters/legacy/$1 [R=301,L]

Why does it only work with a "match everything" expression but not a more specific expression?