Rewrite condition not working?

[eeiswerth]

I have a rewrite condition such as:

RewriteCond %{REQUEST_URI} foo

None of my URLs contain foo, yet my RewriteRule fires.  Am I missing something?

[eeiswerth]

I should clarify, what my rewrite.properties looks like is this:

RewriteCond %{REQUEST_URI} ^foo$

RewriteCond %{HTTP:X-Forwarded-Proto} http

RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [R,L]

The intention is to redirect to HTTPS iff the URL is "foo".