Custom Post Types and Comments Popup

I have created a new custom post type and want to use the WordPress comments popup link to manage adding comments. This works fine for single posts, but when I add this to the custom post type, I am redirected to the actual single CPT post.

For example, if I use the following URL: https://website.com/?comments_popup=14 with a single standard post, I get the comment popup window. However, if I use https://website.com/?comments_popup=141 (where the ID of the post is the ID of the CPT post) and redirected to https://website.com/vbirthday/cpt/post-title/?comments_popup=117 and shown the single display of the CPT post.

Anyone know a way to make the comments popup work with CPT?
I need this urgently! Killing my schedule trying to work around this hiccup.

Thanks
Ed