Cache Trailing Non-Trailing Solution
The cache plugins save the output as a static html file and the visitors see the cached version.
PHP does not work and the visitors see the html file directly.
In this case, non-trailing urls are not redirected to the trailing slash urls. And the visitors see the cached version when both trailing and non-trailing urls are opened as below.
Trailing: http://www.wpfastestcache.com/blog/
None-Trailing: http://www.wpfastestcache.com/blog
Solution
WP Fastest Cache does not have such problem so you don’t need to do anything 🙂