Hello all:
I just wanted to share how I solved this since Wistia is pretty popular for videos. When embedding Wistia videos in a post as an iframe, WPBeaverBuilder was freezing after clicking the publish button. I tried both the video embedding and inserting html, deactivated plugins, etc.
Nothing worked until I installed the Wistia plugin for WP. Once you do that, use the oEmbed option from Wistia along with the video embedding option from WPBeaverBuilder, which by the way is awesome for Youtube videos.
I hope this helps.
Alfonso