Captcha showing on some pages, but not others. HELP!

Hi,

All of the sudden, the captcha images are only showing on some posts and not on others. Even worse, if someone tries to make a comment on the pages that it is not appearing, they are still getting the empty captcha error. Therefore, nobody can leave comments on those pages. My site is very engaged and this is a feature I must have. Please advise what I can do. Thank you!

The site is http://focushereandnow.com

You can look at the latest post to see that the Captcha is not displaying. However, if you go to another post, like the one before..,.it is displaying. However, the post before that is not. I truly hope someone can help me fix this quickly. Thank you!

https://wordpress.org/plugins/si-captcha-for-wordpress/