[Plugin: iframe Shortcode] Works but can't see content that comes after

Hi, I’m trying to use this plugin to embed a YT video at the top of an “About Us” page. The video gets embedded properly and looks great. But all of the text below the video disappears.

I’ve narrowed the problem down to this plugin. When I remove the plugin shortcode and video code, all of the text can be seen.

The site isn’t live yet, so I can’t post a link, but here are two screenshots: https://plus.google.com/photos/112315970278228938541/albums/5786188610376387137?authkey=CLSo_taGq6e4dw

Thanks for your help.

https://www.ads-software.com/extend/plugins/iframe-shortcode/