[Plugin: cbnet Really Simple CAPTCHA Comments] One slight issue with the browser back button

Hello, I’m using the Captcha plugin for my comments. It looks to be working fine (Thank you). I’m calling it in the comments.php file using
<?php cbnet_comment_captcha(); ?>

One issue I’m having, is when the user enters the captcha wrong and the system gives the error telling the user to click the back button and try again. When the user clicks back the captcha doesn’t change, then when the user puts it in correctly it still gives the same error.

The only way around this is to fully reload the page and enter it correctly the first time. Seems like a cache issue. Any idea how to get around this? It doesn’t do the same thing using the captcha on the contact form, but that adds errors under the input instead of requiring to click the back button.

Thanks for any help.

http://wordpress.org/extend/plugins/cbnet-really-simple-captcha-comments/